DEFINITIONS - A NEUROLOGY GLOSSARY
Neurology is terminology-heavy. People often find this hard, and it contributes to the intimidation and avoidance that defines neurophobia.
However, with the exception of eponyms, most terms are highly logical - the issue is just sheer volume, and lack of understanding of the meaning, although it doesn't help that some are Latin and many things have more than one name. Admittedly, the Latin does make terms international - but it can add to perceived 'neurophobia', so I try to use English terms where I can.
Here is a glossary to help people as they work through these cases - and assess neurology patients in the real world.
Eponyms are very common, both in clinical practice and in anatomy - and thus, they're unavoidable, even if they're outdated. Since we're stuck with them, we might as well learn about the people they're named after, so I've added a short section on that at the end, for those interested - by no means 'core knowledge'!
Anatomical terms
General anatomical terms
Aperture - a small window in a structure.
Arcade - a series of arches forming a structure. There are some examples of this which have eponymous names, for example the arcades of Frohse or Struthers - both of which are relevant to nerve entrapment syndromes in the arm.
Arcuate - adjective meaning 'arched', for example the arcuate fasciculus in the caudal medulla - where sensory fibres decussate.
Canal - a narrow passage, usually like a tube or cylinder, and longer than a simple foramen (hole). Different things can pass through it. Below are some examples:
Cavity - a large area containing organs, for example the cranial cavity.
Chiasm -an X-shaped crossing of structures, mainly the optic chiasm - which is often referred to as 'the chiasm'. Pre-chiasmatic and post-chiasmatic are adjectives used in lesions anterior or posterior to the optic chiasm.
Cistern - a CSF-containing space around the brainstem, for example the ambient, crural, and pre-pontine cistersns.
Colliculus - a small mound, usually formed by fibres, such as the facial, inferior and superior colliculi in the dorsal brainstem. The term means 'little hill'.
Commissure - a bundle of nerve fibres connecting both sides of the nervous system. Examples:
Decussation - a crossing over of nerve fibres. Many pathways feature this, connecting one side of the brain to the opposite side of the head or body. 'Decussate' is a verb meaning 'cross over'.
Fasciculus - a bundle of fibres (anglicised as 'fascicle'). This mainly is used for nerve fibres, particularly within brain, brainstem or spine parenchyma. Examples:
Fissure - a separation of lobes or hemispheres of the brain. The great longitudinal fissure separates the two hemispheres, while the Sylvian fissure separates the temporal lobe from the frontal and parietal lobes.
Foramen - a hole, for example those in the skull in which structures (nerves, vessels and the brainstem) pass, or within the CSF ventricles (e.g. foramen on Monro). The plural is foramina.
Fossa - a hollow area that contains a structure. The cranial space is divided into three - the anterior, middle and posterior fossae.
Funiculus - similar to a fasciculus, but thicker - like a 'rope' or stalk. The spinal white matter is organised into these around the grey matter horns -
Ganglion - a group of neuronal cell bodies. The term is used for the peripheral nervous system, including cranial nerves - for example the trigeminal Ganglion.
Genu - this means 'knee', and is used for curved parts of a structure, for example in the corpus callosum or the internal capsule.
Gyrus - an area of grey matter cortex -
Infundibulum - a funnel-shaped structure, mainly the one connecting the pituitary to the hypothalamus.
Lamina - a flat structure, which may connect structures - for example in the vertebrae where the lamina links the spinous process with the pedicles.
Lemniscus - a band of nerve fibres, similar to a fasciculus. The main examples are the medial and lateral lemnisci, involved in tactile and auditory sensory information transport respectively.
Nucleus The region containing the cell bodies of neurons, for example those of each cranial nerve within the brainstem. Lesions in these are referred to as 'nuclear'.
Parasagittal - an adjective for a lesion in the midline between the two hemispheres, particularly tumours. The major one is meningioma, growing on the falx, and the classic presentation is with bilateral leg weakness, mimicking a cord lesion - and easily missed if the brain isn't scanned.
Pars - meaning 'part', for a small portion of something. For example the substantia nigra has a reticular (pars reticularis) and compact (pars compacta) part. The area of the inferior frontal gyrus that houses the expressive language (Broca) area has three pars - opercularis, triangularis and orbitalis. Pars may also refer to part of a sulcus - for example the pars marginalis in the marginal sulcus.
Pedicle - a small connecting segment, like a stalk - as found in the vertebrae.
Ramus - generally a projecting portion of a structure such as nerves (there are dorsal and ventral rami in the spinal nerves) and bones - e.g. the mandibular ramus.
Rostral - adjective meaning, 'at the front'. The nervous system is distinct from other parts of the body in that we use terms that apply to quadripedal animals, but we have an upright position. We use the term rostral mainly for brainstem anatomy in humans, and superior is an acceptable alternative.
Sinus - a hollow cavity whcih may contain air (e.g. the paranasal sinuses) or blood (the venous sinuses in the skull, formed between dural layers).
Somatotopic - an adjective referring to how parts of the nervous system are organised in relation to body parts they represent. The best examples are the motor and sensory homunculi. It also applies to deeper tracts, where there may be separation of fibres to/from the head, arm, trunk and leg (e.g. laterally as in the spinal cord, or anterior-to-posterior as in the internal capsule). Not everything is as simple as 'this area covers this part' - for example it is less clear how the thalamus and cerebellum are organised in somatotopic terms, in comparison to the homunculi. Clearly, somatotopic organisation is very important in localisation!
Stria - a line of nerve fibres. Striae is the plural. Example: the striae medullaris in the fourth ventricle, visible lines running horizontally which carry auditory information to the cerebellum.
Sulcus - a groove in the folded cortex, like a dip between two gyri - enough to separate them into anatomically discrete areas.
Tract - a pathway formed of nerve fibres running in a direction, for example the spinothalamic and optic tracts. A fasciculus is similar but usually over a shorter distance.
Trochlea - from the Greek for 'pulley'. The troclear nerve (IV) is so named as the superior oblique muscle has a sling-like loop (the trochlea) supporting it, attached to the roof of the orbit.
Trigone - a triangular section within a strucutre. Some examples include:
Tunnel - a passageway surrounded by connective tisuse. Tendons may pass through, but for our purposes, peripheral nerves also might, and can become trapped there. The commonest is carpal tunnel syndrome (median nerve, wrist). Another is cubital tunnel syndrome (ulnar nerve, elbow).
Uncus - Latin for 'hook'.
Uncinate - adjective for 'hooked'. There are uncinate processes in some vertebrae.
Ventral - adjective meaning, 'along the front'. The nervous system is distinct from other parts of the body in that we use terms that apply to quadripedal animals, but we have an upright position, so ventral really just means 'anterior' in humans. The other related terms are dorsal, caudal, rostral.
Ventricle - a fluid-filled cavity. In the brain there are several - two lateral ones, the third, and the fourth.
Specific anatomical structures
Aqueduct - the CSF channel in the centre of the midbrain
Arcuate fasciculus - a white matter tract linking the receptive and expressive language areas.
Basion - the anterior margin of the foramen magnum.
Brachium conjunctivum - the superior cerebellar peduncle.
Calcarine sulcus - a dividing line between the upper and lower parts of the occipital lobe. Visual fibres terminate here, and those from the upper quadrant deposit on the cortex below the calcarine sulcus, vice versa for those from the lower quadrant. On an antero-posterior line, the more peripheral fibres deposit anteriorly, while those from the central part of vision deposit at the posterior pole.
Cavernous sinus - there are two of these, each formed between the two layers of dura (meningeal and periosteal) containing venous blood, lying either side of the pituitary fossa. Several structures pass through - the carotid artery, the sympathetic nerves, and nerves V1, V2, III, IV and VI. Lesions produce combinations of deficits in these - the 'full house' picture causes complete ophthalmoplegia and numbness of the V1 and V2 areas in the face.
Choroid plexus - structures in the ventricles which form and secrete cerebrospinal fluid (CSF). Rarely a tumour can arise from the cells forming a papilloma, mainly in children - with risk of hydrocephalus.
Claustrum - a thin strip of grey matter in between the putamen and the insula.
Clivus - a sloped part of the skull base, formed by fusion of the occipital and sphenoid bones. It lies anterior to the foramen magnum. The brainstem sits above it. Nerve VI runs directly above it, taking a long, uphill path, which is why it is vulnerable to disruption in raised intracranial pressure states. Clivus lesions include cancer (e.g. chondrosarcoma) and osteomyelitis. The combination of VI and XII palsy is called Clivus syndrome, or Gotfredtsen syndrome.
Corticobulbar tract - neurons from motor cortex to various brainstem nuclei, providing supranuclear input. The nuclei give neurons involced in functions such as facial and jaw movement, speech and swallowing.
Corticospinal tract - motor output from the brain through the subcortical space, brainstem (crossing in the pyramids) and contralateral spinal cord white matter. At each level, branches enter the cord grey matter and synapse with the lower motor neuron in the ventral horn, which then leaves in the ventral root.
Culmen - a section of the cerebellum, best seen in sagittal views at the midline.
Declive - a section of the cerebellum, best seen in sagittal views at the midline.
Default mode network - a connected series of regions including the medial prefrontal cortex and posterior cingulate cortex inolved in thinking, ruminating, daydreaming and other 'conscious' functions, which may be dysfunctional in states such as depression
Dentate gyrus - part of the hippocampus, involved in memory formation.
Dentate nucleus - the most lateral of the four cerebellar nuclei and by far the largest. A bit like the olive, it is folded and shaped like an open ring. It takes inhibitory Purkinje neuron signals from the cerebellar hemispheres (posterior lobe). It sends excitatory neurons to the contralateral ventrolateral thalamus - both directly and some via the red nucleus - as the dentatorubrothalamic tract. This crosses after the superior cerebellar peduncle in the caudal midbrain. Lesions in the tract cause ipsilateral ataxia if proximal to this crossing (cerebellar, peduncle) but contralateral if distal (midbrain) - e.g. Claude syndrome.
Dentatorubrothalamic tract - dentate (cerebellar) to the contralateral thalamus (specifically ventrolateral). Some of these neurons synapse in the red nucleus as an intermediary. Involved in motor coordination - this happens before the final corticospinal output. Lesions cause ataxia and also tremor (e.g. Holmes). This is ipsilateral if below the decussation, contralateral if above it.
Diencephalon - the thalamus and hypothalamus, as well as the pineal body and posterior pituitary
Dorsal longitudinal fasciculus (of Schutz) - a tract connecting the hypothalamus with the periaqueductal gray area, reticular formation and some autonomic nuclei (involved in functions such as salivation, gastrointestinal and cardiac outputs)
Dorsum sellae - part of the sphenoid bone, behind where the pituitary gland sits
Extrastriate cortex - various parts of the occipital cortex outside of the primary visual cortex (V1). These have functions more about the interpretation of things we see rather than the primary function of vision, so lesions don't cause primary loss of vision but other phenomena, such as problems with recognising movements (akinetopsia)
Falx cerebri - a large sheet of dura in the great longitudinal fissure, separating the hemispheres.
Falx cerebelli - a small dural sheet separating the cerebellar hemispheres. The occipital sinus (a venous blood channel) is within this.
Fastigial nucleus - the most medial of the four cerebellar nuclei. It takes inhibitory signal from the Purkinje cells of the vestibulocerebellum (nodulus and flocculus). It projects back to bilateral vestibular nuclei via fastigiobulbar efferent fibres.
Fastigiobulbar tract - the fastigial nucleus in the cerebellum takes input from the flocculonodular part (which processes vestibular signals). The nucleus then sends neurons back to bilateral vestibular nuclei in the brainstem. The tract is part of the vestibulo-cerebellar system involved in balance, posture and eye movements.
Flocculus - a section of the vestibulocerebellum, best seen from the front - it forms a small separate lobule either side of the pons. Along with the nodulus, it takes vestibular afferent information - both second-order neurons (after the vestibular nuclei) but also direct input (first-order neurons)from the vestibular nerve. It's efferent connections are inhibitory (GABA), like all cerebellar cortical output. They project to the vestibular nuclei bilaterally some directly, and some via an initial synapse in the fastigial nucleus.
Folium - a section of the cerebellum, best seen in sagittal views at the midline.
Frontal aslant tract - a white matter tract in the frontal lobe that links the supplementary motor area to the motor language areas (of Broca). Damage can affect speech production - for example if it is injured during neurosurgery.
Geniculate ganglion - the anterior 'bend' in the facial nerve within its canal, where the sensory fibres' cell bodies are. Affected in Ramsay-Hunt syndrome (Varicella Zoster reactivation causing painful facial palsy with ear canal vesicles)
Geniculocalcarine tract - from the lateral geniculate nucleus to the primary visual cortex either side of the calcarine fissure. This is more often called the optic radiation, and it splits into superior and inferior divisions.
Globus pallidus - part of the basal ganglia, medial to the putamen. It has internal and external parts. The adjective for things related to it - such as tracts and disorders - is 'pallidal'.
Inferior longitudinal fasciculus - a tract connecting the occipital and temporal lobes. This allows the ventral stream system to help us make sense of what we see, in particular through functions such as face recognition
Inferior olive - a nucleus on either side of the ventral upper medulla, which projects 'climbing' fibres to the cerebellum.
Insula - a deep part of the cortex tucked inside the Sylvian fissure.
Internal arcuate fibres - the dorsal column-medial lemniscus pathway fibres reach the caudal medulla, synapse in the arcuate nucleus, then project the internal arcuate fibres, which decussate and ascend in the medial lemniscus.
Jugular ganglion - part of the vagus nerve in the jugular foramen; the superior of two ganglia.
Lateral lemniscus - ascending auditory pathway in the upper brainstem on its way to the inferior colliculi (dorsal midbrain) and from there, to the medial geniculate nucleus of the thalamus. Sound information is carried bilaterally in the tract, so unilateral lesions do not cause hearing loss.
Mamillothalamic tract - output from the maxillary bodies to the ventral thalamus as part of the Papez circuit, involved in memory.
Medial forebrain bundle - limbic parts of the brain related to reward and emotional functions connect to the hypothalamus. Particularly the ventral tegmental area which makes dopamine.
Medial longitudinal fasciculus - a vertical bundle of fibres linking the nuclei of nerve VI (pons) with nerve III (midbrain), allowing binocular conjugate gaze.
Medullary velum - two sheets of white matter forming the roof and floor of the fourth ventricle, behind the medulla.
Mesencephalon - the midbrain
Neuroretinal rim - an area between the outer border of the optic disc and the cup in its centre.
Nigrostriatal tract - neurons from the substantia nigra pars reticulata project to the putamen (part of the striatum). They signal onto D1 and D2 receptors which have different effects and work via the direct and indirect pathways respectively.
Nodose ganglion - part of the vagus nerve in the jugular foramen; the inferior of two ganglia. Contains the cell bodies of afferent nerves from the body, travelling to the nucleus solitarius in the medulla.
Nucleus (...)
Nodulus - a section of the vestibulocerebellum, not visible from the outside - it's sited medially and can be seen in sagittal and axial views. Along with the flocculus, it takes vestibular afferent information - both second-order neurons (after the vestibular nuclei) but also direct input (first-order neurons)from the vestibular nerve. It's efferent connections are inhibitory (GABA), like all cerebellar cortical output. They project to the vestibular nuclei bilaterally some directly, and some via an initial synapse in the fastigial nucleus. The vestibular nuclei then project downward in vestibulospinal tracts and upwards in the medial longitudinal fasciculus (to coordinate eye movements).
Nucleus interpositus - the globose and emboliform nuclei in the cerebellum are grouped together functionally and called this. They take inhibitory projections from Purkinje cells from the vermis. They send excitatory projections to the contralateral red nuclei in the midbrain, which then send the rubrospinal tracts (which decussate again on descent). This is a typical ‘cerebellar’ pattern of double crossing. Ipsilateral lesions might therefore affect unilateral posture but in practice the nuclei are so medial that the issue is often bilateral, with clinical evidence of unsteadiness of stance/gait.
Obex - the most caudal part of the 4th ventricle, below which it becomes the central canal of the spinal cord. The term is latin for 'barrier'.
Operculum - the term means 'lid' or 'cover'. This is an area where the frontal, temporal and parietal lobes lobes converge either side of the Sylvian fissure. The insular cortex is on the inner aspect of this - covered by the operculum.
Opisthon - the posterior margin of the foramen magnum.
Optic sheath - the optic nerve is surrounded by arachnoid and dura, with CSF around it. The optic sheath is this casing. It can become dilated when ICP is raised, visible on imaging, and associated with papilloema, and a window is sometimes made in it surgically to relieve this (fenestration). It can also develop meningiomas, causing visual loss - mainly in midde-aged women.
Pallidothalamic tract - a short tract connecting the globus pallidus interna (GPi) to the thalamus. This is inhibitory and functions tonically like a brake. The putamen inhibits the GPi, effectively taking this brake off and enabling movement.
Paramedian pontine reticular formation - a centre in the dorsal caudal pons involved in conjugate lateral gaze to the same side.
Piriform cortex - part of the primary olfactory cortex, relevant to the sense of smell. It takes signal from the olfactory nerve. This sensory system doesn't relay via the thalamus - unlike sight, hearing and touch.
Pontocerebellar tract - pontine nuclei take input from the cortex as part of a pre-motor system. They then project transverse fibres which decussate and travel to the cerebellar cortex via the middle cerebellar peduncle on each side. These fibres account for a huge part of the anterior bulk of the pons and wrap around the descending corticospinal tracts. They are the reason that basal pontine lesions often feature ataxia and dysarthria. The ataxia may be contralateral, along with contralateral hemiparesis - hence, ‘ataxic hemiparesis’ (a classic pontine lacunar stroke syndrome).
Restiform body - the inferior cerebellar peduncle.
Retroepicondylar groove - the area behind the medial epicondyle of the humerus where the ulnar nerve runs. Compression here can trigger the 'funny bone' sensation we all know
Rostrum - an anterior, curved part of the corpus callosum. The term means 'beak'. It is below the genu, which is the most anterior part.
Rhombencephalon - the medulla, pons and cerebellum; otherwise known as the hindbrain
Rubrospinal tract - the red nucleus (midbrain) sends neurons to the spine, which cross in the caudal midbrain. They influence upper arm musculature, causing flexor (biceps and grip) action and inhibiting extensors. The major relevance is decerebrate posturing: major brain damage including the midbrain causes unconsciousness with posturing with arms extended, induced by painful stimulus or happening spontaneously.
Semilunar lobule - a section of the cerebellum, best seen from the front.
Spinal trigeminal tract - facial and oral pain and temperature sensation enters the pons via nerve V, then the first-order neurons descend on the ipsilateral side as the descending spinal trigeminal tract - passing through the dorsolateral medulla and into to the C-spine, until C4. Along the way they send branches which synapse with the spinal trigeminal nucleus, which is long, spanning this length (hence ‘spinal'). The nucleus is somatotopic, with lower segments corresponding to the outer parts of the face and the upper segments to the the inner parts including the mouth. After synapsing, the second order neurons at all levels cross, and ascend (ascending spinal trigeminal tract), joining the trigeminothalamic tract above.
Spinocerebellar tract - tracts carrying proprioceptive information to the cerebellar vermis and paravermis. There is a dorsal and ventral tract on each side. They both feed into the cerebellum on the same side but with a different route. The dorsal tract doesn't decussate and enters via the inferior cerebellar peduncle in the medulla. The ventral tract decussates twice and enters via the superior cerebellar peduncle in the midbrain and pons. Another is termed the rostral spinocerebellar tract - essentially the upper limb's answer to the ventral tract. Similarly the cuneocerebellar tract is the upper limb equivalent of the dorsal tract.
Spinothalamic tract - second-order neurons carrying pain and temperature synapse in the spinal cord grey matter then cross anterior to the central canal (Lissauer's tract) and ascend in the lateral cord white matter. They continue all the way through the brainstem travelling in the dorsolateral aspect, then synapse in the ventroposterolateral thalamus. The third order-neurons (thalamocortical) then ascend to the primary sensory cortex.
Striatum - the caudate, putamen and nucleus accumbens
Subiculum - part of the parahippocampal gyrus, below the dentate gyrus - relevant to memory and epilepsy.
Substantia innominata - part of the basal forebrain which is important for the cholinergic supply to the brain. Affected in Alzheimer's. The name, ironically, means 'unnamed substance'.
Substantia nigra - a melanin-rich zone in the ventral midbrain, deep to the peduncles, which projects nigrostriatal neurons to the putamen.
Superior longitudinal fasciculus - a tract connecting the various lobes of the brain within one hemisphere. It starts in the frontal lobe and works backward, and some of it goes straight the occipital lobe while other fibres arc down and anteriorly into the temporal lobe.
Tectum - the most dorsal part of the midbrain, posterior to the aqueduct. The inferior and superior colliculi are here. The adjective 'tectal' refers to this region, and 'pretectal' for the area just above this.
Tegmentum - the dorsal part of the upper brainstem (pons and midbrain), next to the CSF channel (fourth ventricle for pons, aqueduct for midbrain). It is clinically important as there are so many nuclei and tracts within it, so tegmental lesions produce deficits.
Telencephalon - the hemispheres and cortex, basal ganlgia and limbic system.
Thalamocortical tract - outputs from the thalamus to ipsilateral cortex. there are many of these and signals carried include sensory (to parietal) and pre-motor from the basal ganglia (to the motor cortex).
Torcula - also known as torcula Herophili after a Greek anatomist. A junction point where the superior sagittal sinus converges with several others - including the straight sinus (which drained the central, deep parts of the brain), the occipital sinus (draining the occipital area) and then the two transverse sinuses, which the blood empties into before leaving the intracranial zone (via the sigmoid sinuses and then jugular veins).
Trigeminal impression - a hollow zone in the petrous temporal bone's apex. The trigeminal ganglion sits here within Meckel's cave.
Trigeminothalamic tract - otherwise known as the trigeminal lemnsicus and quintothalamic tract. The ascending tract carrying second-order facial and oral sensation to the thalamus, contralateral to the side innervated. It is the common output of different sensory pathways (touch, pain/temperature and proprioceptive) that diverge before reuniting. T
Tuber - a section of the cerebellum, best seen in sagittal views at the midline.
Uncinate fasciculus - a white matter tract linking the limbic (temporal) regions with the frontal lobe, involved in behaviours and how they relate to emotion
Ventral tegmental area - part of the midbrain which supplies dopamine to higher brain centres including the nucleus accumbens, relevant to reward pathways.
Vestibulospinal tract - the vestibular nuclei project to the spine with medial and lateral vestibulospinal tracts, influencing posture:
Zona incerta - a region between the thalamus and subthalamic nucleus, important in the area of deep brain stimulation surgery for Parkinson's disease and other movement disorders
Eponymously-named anatomical structures
Annulus of Zinn - a fibrous ring in the orbital apex - the rectus muscles which move the eye are attached to it.
Arcade of Frohse - a membranous edge on the supinator muscle. The posterior interosseous nerve, a motor-only branch of the radial nerve, can become trapped against this, producing wrist and hand weakness (in extensor muscles only).
Arcade of Struthers - a band of connective tissue in the medial head of the triceps. It can sometime strap the ulnar nerve above the elbow.
Arnold's nerve - the vagus (X) has a branch in the ear, giving sensation, and stimulation of it can cause coughing. Also known as Alderman's nerve.
Artery of (...) - there are many of these, with examples below. Some are normal structures, while others are variants that can cause unusual syndromes.
Ciliospinal centre of Budge - part of the sympathetic tract in the C8-T2 spinal cord, where the first- and second-order neurons synapse. It's involved in pupillary dilatation - lesions cause Horner's
Circle of Willis - the central 'roundabout' at the base of the brain, with a single posterior input (the basilar artery, from both vertebrals) and bilateral anterior input (the internal carotids). The vessels perfusing the brain, brainstem and cerebellum all emerge from this.
Clarke's column - neurons in the spine involved in carrying proprioception from the legs
Dorello's canal - a small area next to the petrous temporal bone apex, which the abducens nerve (VI) passes through.
Fissures of Santorini - natural spaces in the ear canal. The main clinical relevance is that they are a route for ear infection (otitis externa) to spread into the temporal bone, causing osteomyelitis. The usual culprit is Pseudomonas, typically in older people with diabetes.
Foramen of Luschka - there are two of these CSF exit spaces, also known as lateral apertures - which project laterally out of the fourth ventricle. CSF leaves it and drains into the subarachnoid space.
Foramen of Magendie - a central hole in the posterior part of the fourth ventricle. CSF passes through it and drains into the cisterna magna - a large CSF space below the cerebellum.
Foramen of Monro - the name is singular, but there are two of these CSF channels, linking the two lateral ventricles with the third ventricle. They slope diagonally and inferiorly towards the centre.
Gasserian ganglion - the trigeminal ganglion.
Gruber's ligament - the petroclinoidal or petrosphenoidal ligament, which (as the name suggests) forms a band from the petrous temporal bone to the anteroir clinoid process on the sphenoid bone, and forms the roof of Dorello's canal. The abducens nerve (VI) passes below it, before entering the cavernous sinus.
Heschl's gyrus - part of the primary auditory cortex, hidden within the Sylvian fissure. The proper name is the transverse temporal gyrus.
Interstitial nucleus of Cajal - a structure in the midbrain involved in vertical gaze.
Kernohan's notch - not so much a specific structure as a condition, with brain herniation pushing the contralateral cerebral peduncle against the tentorium, leading to hemiparesis ipsilateral to the lesion in the hemisphere which drives the herniation - a false-localising sign
Lissauer's tract - just before the axons carrying pain and temperature synapse in the grey matter, they rise 1-2 segments on the side of entry in Lissauer's tract, then enter the dorsal horn.
McRae line - an imaginary line drawn between the opisthon and basion either side of the foramen magnum. The depth of cerebellar tonsilar descent is measured against this reference line, defining Chiari malformations (minimum 5mm below it).
Meckel's cave - a pocket of dura folded back on itself, which the trigeminal ganglion sits in. It is not a complete encasement, unlike other structures such as the venous sinuses - it is more like a 'sleeve'.
Merkel corpusle - touch receptors in the skin which detect pressure
Meyer's loop - the inferior radiation of the second-order neurons in the visual pathway, distal to the lateral geniculate nucleus (thalamus). It travels in the temporal lobe and carries vision from the contralateral upper quadrant (from both eyes). It terminates in the occipital cortex below the calcarine sulcus.
Nodes of Ranvier - peripheral nerves have myelin sheaths, and the gaps in these are called nodes of Ranvier. The electrical signals jump across these, which is known as saltatory conduction
Nucleus of (...)
Organ of Corti - part of the inner ear in the cochlea involved in hearing
Papez circuit - a multi-neuron loop involved in memory, projecting from the hippocampus through the fornix, mamillary bodies, thalamus and cingulate gyrus.
Perlia's nucleus - a midbrain structure involved in eye movements
Rexed laminae - the spinal cord grey matter is H shaped, and divided into 10 layers termed laminae
Rolandic cortex - the pre- and post-central gyri (motor and sensory strips)
Struthers' ligament - not everyone has this. A fibrous band in the distal humerus linking the supracondylar region to the medial epicondyle. The median nerve passes below it, so it can cause entrapment here - with a very proximal median nerve lesion, and a broad set of deficits as a result. (Note - this is distinct from the arcade of Struthers)
Sylvian fissure - this is the lateral fissure which separates frontal and parietal lobes (above and medial) from the temporal lobe (below and lateral).
Triangle of Guillain-Mollaret - a triangle of the red nucleus and inferior olive on one side and the dentate nucleus on the other. Damage can lead to disinhibited growth of the olive, so-called hypertrophic olivary degeneration - associated with palatal myoclonus.
Vein of (...)
Wernekink's commisure - an area in the paramedian caudal midbrain where both superior cerebellar peduncles cross. Bilateral damage can cause bilateral ataxia, dysarthria and gaze palsies due to oculomotor damage.
Wilbrand's knee - this is disputed. In the optic chiasm, the inferior nasal fibres are said to arch somewhat forward, almost joining the opposite optic nerve, before turning backwards to travel toward the optic tract. It was thought that compressive lesions (particularly meningioma) could lead to ipisilateral blindness from optic neuropathy as well as contralateral superior temporal quadrantanopia - so-called junctional scotoma - but the concept is debated now.
Symptoms
Ageusia - loss of taste sensation. Can happen in the unilateral tongue from facial nerve damage.
Akinetopsia - inability to see things when they move, but normal ability to see them when still. Caused by damage to the dorsal stream - which handles processing of primary visual signals already received in the occipital lobe.
Alexia - inabilty to read. There are various subtypes.
Allodynia - a normally painless stimulus becomes painful. If you've ever had sunburn, this is what bedsheets cause. In neurology it can reflect neuropathic pain, whether from nerve or spine damage, as well as thalamic disease.
Amnesia - memory loss. This can be for new events (anterograde amnesia) or previous ones (retrograde amnesia). It has many causes. In dissociative amnesia (a psychogenic response to trauma) people lose memory of large periods of their life, sometimes their entire autobiographical history.
Amusia - acquired loss of ability to perceive music, specifically tones - but without primary problems with hearing. Usually a right middle cerebral artery stroke causes this.
Chewing fatigue - tongue ischaemia during actions such as speech and eating, caused by vasculitis affecting the perfusing arteries. Seen in giant cell arteritis (also known as temporal arteritis).
Clumsiness - a vague term, which to us (trained medical professionals) may imply ataxia but shouldn't. This generally means difficulty with tasks like holding items, performing fine motor tasks (shoelaces, jewellery, bra straps, buttons etc), though may also imply a tendency to make errors during what should be smooth, controlled actions such as reaching, with a tendency to spill things, knock things over or miss targets. When this word is used, or job is to ask about the specific problems the patient is having, and this should give us an idea of what we might find on examination.
Depersonalisation - the feeling that the person is not real or themselves, or is detached from their body, as if watching from outside of it. A feature of dissociation.
Derealisation - the feeling that things are not real. It may also feel like being in a dream, a trance, in fog, or floating. A feature of dissociation.
Diplopia - double vision. If this is only present with both eyes open it's binocular - the eyes are not lining up properly. If it's still present with one eye open it's monocular - there may be a lens/focusing issue. If the patient has diplopia with both eyes open, then with only the right eye open, then with only the left eye open - this is bilateral monocular diplopia, and is usually functional. Note - many patients report 'double vision' to actually mean blurred vision, or the world appearing in motion (vertigo). Always ask what is actually meant.
Dizziness - an incredibly common symptom though an imprecise term. People may mean any of the following:
Dysaesthesia - an unpleasant sensation, for example burning or itch.
Dyschromatopsia - altered or reduced colour vision. Can reflect optic nerve damage (e.g. neuritis) but also temporal lobe damage, particularly the right fusiform gyrus in the basal temporal lobe.
Dysphagia - impaired ability to swallow. This can be from neurological causes (such as stroke, neurodegenerative or neuromsucular disorders), but can also be due to mechanical problems such as obstructive masses. Please don't confuse it with dyphasia!
Dysphasia - impaired language function. This isn't 'speech disturbance' - many who can't speak have intact language function, but dysphasia does interfere with spoken communication. It also interferes with written language. It can be expressive, receptive, or both.
Hallucination - an abnormal sensation in the absence of an actual stimulus, particularly auditory, visual, or olfactory. We don't really refer to simple tactile sensations such as paraesthesia as hallucinations, even though they are; we tend to use tactile hallucination to mean other sensations such as insects under the skin (formication).
Hyperacusis - increased hearing. You might think this is desirable, but it isn’t - background noises become irritating, and sometimes the patient’s own movements (e.g. chewing) become audible. An important cause is lower motor neuron facial palsy if the lesion is within the temporal bone, affecting the nerve to stapedius, for example Bell’s palsy and Ramsay-Hunt syndrome. More distal lesions (e.g. at the parotid gland) do not cause this.
Hyperorality - a tendency to put items into one's mouth, seen with loss of inhibition in frontal lobe disorders, particularly behavioural variant frontotemporal dementia. The items include food, and binge-eating may be present even to the point of choking episodes, but also non-edible substances, for example toilet paper. This is different to pica, in which people eat non-nutritional substances such as soil or ice, and can be seen in autism but also pregnancy and iron deficiency.
Lingual claudication - tongue ischaemia during actions such as speech and eating, caused by vasculitis affecting the perfusing arteries. Seen in giant cell arteritis (also known as temporal arteritis).
Macrosomatognosia - the illusory perception that part of the body is larger than it is, for example the arm. This is typically due to a parietal problem such as a seizure or migraine aura.
Micropsia - things appear smaller than they are. Macropsia is the opposite.
Moore's lightning streaks - a benign symptom in older people. Eye movement in low-light situations causes vertical flashes of light in the temporal visual fields. Unlike retinal detachment which causes a ‘shower’ of sparks, Moore's lightning streaks are individual and brief.
Neuralgia - pain in the distribution of a nerve, often provoked by movements, actions or skin contact. Usually very painful, with brief, shock-like attacks. Often there's a refractory period between attacks - there is residual pain but the brief, excruciating shocks are not possible for a period.
Numbness - formally this should mean 'loss of feeling', but very often it is used to mean 'weakness' or particularly, difficulty using the hands. The converse is true - true numbness is often interpreted as weakness even in the absence of actual loss of ability to generate force. Numb hands do simply feel weak!
Oculodynia - eye pain. It's quite common in a range of headaches, particularly migraine, but if there's pain moving the eye this can suggest optic neuritis.
Odynophagia - pain on swallowing. This usually is not neurological, but glossopharyngeal neuralgia is a cause.
Oscillopsia - jumping vision. This can happen for a few reasons. Nystagmus may cause it. Bilateral vestibular disease also can, when patients are walking on uneven ground - as the vestibulo-ocular relex is impaired, so they cannot hold focus as the head position constantly shifts.
Palinopsia - after-images. Moving images leave a trail, similar to a long-exposure photograph, or may persist in one place even after the object has moved. Sometimes patterns (for example on someone's clothes) are projected wherever the patient looks, for example onto walls.
Phantosmia - an olfactory hallucination. This has many causes. If brief, recurrent and stereotyped it can suggest focal seizures. If persistent, it can be due to migraines, as well as pregnancy.
Phosphenes - flashes in vision. A major cause is migraine aura but these can also be seen with occipital seizures and other occipital lesions - including ischaemic stroke (which does not 'just cause negative symptoms'...).
Singultus - hiccups. Nobody uses this term, really. It can signify various pathologies, including diaphgragmatic region diseases such as abscess - but in neurology lesions of the medulla can feature it, including area postrema syndrome.
Teichopsia - shimmering zig-zag lines seen in migraine aura. Often with a rainbow-like iridescence in them. Teichos is Greek for a town wall, and they look a bit like the structure of old walls.
Tingling - pins and needles or paraesthesia are other words for this. Unusual sensations in an area of the body that feel like vague electricity or little pinpricks or sometimes cold skin.
Tonic spasms - demyelination in the spinal cord leads to delayed emergence of involuntary muscle contractions and posturing in one or more limbs. Pain is often present. Attacks may be triggered by movement, including turning in bed. Carbamazepine helps relieve them.
Tulio phenomenon - sounds, including the patient's own actions, create vertigo and nystagmus. A feature in superior semicircular canal dehiscence - the canal lacks a bone insulating it.
Weakness - inability to generate a normal amount of force in a given muscle, several, or the entire body. Weakness may be focal, involving a specific region (e.g. a hand, a leg), multifocal, involving several separate regions, or global (diffuse), involving the entire body.
Xerostomia - a dry mouth. There are various reasons this can be seen in neurology. It's a side effect of many drugs, including anticholinergics and tricyclics. It can be seen in Sjogren's as part of the sicca syndrome (with other dry membranes e.g. eyes or genital). Damage to the nerves to the parotid (IX), submandibular and sublingual (both VII) glands can also produce it.Signs
As a brief foreword, a number of these are signs but also symptoms. The patient may or may not report them. In practice the division between symptoms and signs is a little arbitrary, likewise the history and exam being separate exercises. We can see many signs on display while we take the history, including what the patient does as well as what they say - and how they say it.
Eponymous signs and tests
Babinski sign - a cutaneous, not tendon, reflex. Stroking the lateral sole of the foot makes the big toe up and the others fan out. This indicates upper motor neuron damage. Be careful not to confuse a ticklish withdrawal reflex with this.
'Other' Babinski sign - in hemifacial spasm, the eyebrow elevates on the contracting side
Bell's phenomenon - closing the eyes forcefully leads to both eyes rolling up. This is a defensive response and is normal - we can't see it unless the eyelids are passively held open. In lower motor neuron facial paralysis it is evident when the person tries to close the eyes. In functional (not deliberate) or feigned (deliberate) unresponsive states, people resist passive eye opening, and if the lids are lifted Bell's phenomenon is evident.
Brudzinski's sign - passively flexing the neck causes hip and knee flexion in meningeal irritation (particularly infectious). As with Kernig's sign this is specific (if you see it it's suggestive), but not sensitive (most people with meningism won't have it).
Bruns nystagmus - damage in the lateral pons or medulla causes two effects - vestibular and cerebellar peduncle damage. The classic is a cerebello-pontine angle. Two types of nystagmus arise, seen in horizontal gaze at either side:
Chaddock sign - stroking in an arc under the lateral malleolus causes great toe extension - an alternative to the Babinski test, often better-tolerated in ticklish people.
Cheyne-Stokes breathing - cycles of respirations slowing to a pause of several seconds, then picking back up as the CO2 level rises. This is seen in people who are dying - in general - but can be seen due to brain damage.
Chvostek's sign - low calcium causes tetany (neuromuscular hyperactivity). Tapping the side of the face near the jaw angle causes facial twitching.
Dix-Hallpike test - benign paroxysmal positional vertigo (BPPV) is due to crystal build-up in the semicircular canals, with specific head movements triggering attacks. The Dix-Hallpike test is one of several manouevers to induce an attack. The patient's head is turned outward then held somewhat upside down, and after a few seconds' latency nystagmus (upbeat, torsional) begins, accompanied by symptoms. The test is only positive with the nystagmus - the vertigo is not enough!
Eye-relatedFroment's sign - we can normally pinch a sheet by adducting the thumb to the index finger. In ulnar neuropathy this is weakened, so the patient flexes the thumb to compensate, using the flexor pollicis longus muscle - innervated by the anterior interosseous nerve (median).
Gower's sign - proximal myopathy prevents people getting up from the ground, so they use their arms to form a base, then walk their hands back to help them stand.
Hennebert sign - pushing on the tragus creates a pressure wave in the ear, and nystagmus arises. A sign of a perilymphatic fisula - also known as the fistula test.
Hoover's sign - a sign of functional weakness. It relies on showing voluntary weakness but intact involuntary strength, using a movement (hip flexion) that requires contralateral hip extension:
Hoffman's sign - flicking the distal phalanx of the middle finger makes the thumb and index finger contract as if briefly pinching. A sign seen in upper motor neuron lesions, particularly cervical cord damage - but it can also be seen in healthy, anxious people (like many we see in clinic!)
Holmes rebound test - the patient holds their hands outstretched, and you push down and tell them to resist, then release. In cerebellar disease the arms rise up then rebound downward, due to loss of agonist-antagonist coordination.
Holmes tremor - a slow, large amplitude tremor including distal and proximal movements, and present at rest and on actions, related to damage in the midbrain or thalamus (also known as rubral and thalamic tremor - both of which are different structures but linked). This usually emerges after a delay from insults such as midbrain haemorrhage and demyelinating attacks - so is probably a form of release phenomenon, or related to re-wiring after injury.
Hutchinson's sign - a shingles vesicle on the tip of the nose predicts broader V1 involvement, which can threaten the eye. Spotting this should trigger very careful eye care to prevent blindness.
Kernig's sign - passively lifting the leg bent, then extending the knee, triggers pain. This is specific for meningeal irritation (particularly infectious) but not sensitive - meaning you'll not see it in most people but if you do see it, it's suggestive of meningitis.
Lasegue sign - passively flexing leg triggers radicular pain down the back of the leg. If this is the same pain the patient has been suffering, it supports radiculopathy, usually from a lateral disc prolapse affecting L5 or S1.
Lhermitte's sign - this is a symptom, not a sign, although you could also demonstrate it in clinic. I've put it here as people tend to call it a sign - really, it's a phenomenon. Neck flexion causes electric shocks into the limbs and down the back. The best-known cause is demyelination but it can be caused by many forms of damage.
Luria test - a sequence of three hand actions is shown to patients and they are asked to repeat it. Those with cognitive problems struggle to learn it. It doesn’t discriminate between individual causes of cognitive impairment and it wasn’t developed for neurodegenerative disease - the area it is most usually applied in.
Myerson's sign - tapping the glabella causes us to blink, but we usually habituate (stop after a few taps). In Parkinson's this habituation is lost and blinking continues with further taps. This test can look somewhat rude so it is important to at least explain what you are about to do (even if you don't say what you expect to see, which could influence behaviour).
Oppenheim sign - one of many alternatives to the Babinski. Running the thumb down the tibia causes the great toe to extend.
Pulfrich effect - more a symptom than sign but you may note it on examination. Demyelination of the optic nerve affects the transmission speed of visual input relative to the intact eye. An object moving across the vision appears to take a curved arc due to this imbalance.
Riessman's sign - a bruit heard on auscultation of the closed eye. The original description was in Graves disease but carotid-cavernous fistulas can cause this.
Rinne test - if the base of a tuning fork is placed on the central forehead, both ears should hear it to the same amount. If one ear has hearing loss, we can compare what both sides hear. Conductive hearing loss will increase resonance on the affected side, making it sound louder during the test - whereas sensorineural hearing loss will reduce the perceived sound, so it seems quieter.
Romberg's sign - we rely on eyes, ears (vestibular signals) and feet (proprioception) to balance. We can function with only two of these but not one. Closing the eyes can expose a fault in either of the remaining two, with people losing balance if not supported. First described in syphilis in the pre-treatment era - dorsal column disease (tabes dorsalis) was a common feature
Roos' test - for neurogenic thoracic outlet syndrome. The patient adopts the ‘surrender’ ‘hands up!’ position - 90° for each of shoulders abduction, elbow flexion and external rotation. They then open and close their hands for 3 minutes. If numbness, tingling and pain develop this is positive. As with many such tests it isn't specific.
Spurling's test - a provocative maneuver for pain and tingling due to cervical radiculopathy. The neck is extended, then laterally flexed and rotated towards the side being tested (e.g. left arm). The head is then compressed by the examiner with both hands from above. Reproducing the patient's symptoms is supportive evidence. The problem is it isn't specific - people who don't have cervical radiculopathy may also report symptoms. It's also unpleasant, so warn the patient before.Tinel's test - tapping a nerve causes tingling distally. This is useful to provoke symptoms, particularly in median and ulnar entrapment neuropathies. It doesn't work for motor-only nerves (e.g. posterior interosseous), and with advanced entrapment neuropathy it can be negative as the nerve is dead.
Unterberger test - marching on the spot, eyes closed and arms extended, can lead to rotation to one side in unilateral vestibular disease. The rotation is towards the affected side, which helps with lateralisation - in addition to other tests such as the head impulse test. The patient may simply display Romberg's sign and fall over however - making Unterberger's test impossible...
Uthoff's phenomenon - transient worsening of deficits due to multiple sclerosis triggered by heat - whether exercising, warm weather, in the shower/bath, or during fever. Sometimes these are chronic deficits which are always present and simply intensify. Other times the deficits are absent in normal conditions but re-emerge with heat. The patient may not have known of the initial relapse, so they may simply report the intermittent features.
Wartenburg reflex (corneomandibular reflex) - touching a cornea causes the jaw to deviate to the opposite side. It’s seen in coma with brainstem damage. Normally this wouldn’t happen due to descending inhibitory influence on the reflex, but if this is lost the ipsilateral pterygoid is stimulated, leading to contraction, and jaw deviation. It suggests a poor prognosis.
Wartenberg's sign - ulnar neuropathy causes the little finger to naturally abduct from the ring finger. This seems confusing at first - the abductor digiti minimi (ADM) is an ulnar-innervated muscle - but the cause here is loss of adductor (lumbrical) action and unopposed action from the extensor digiti minimi, a radial-innervated muscle.
Weber test - normally, air conduction is louder than bone. In hearing loss this ratio may or may not change, which helps us work out the cause. A tuning fork with the prongs held near the ear tests air conduction - this can be compared to the base being placed on the mastoid (bone conduction). If bone conduction is louder than air conduction this is conductive hearing loss, while if air conduction is louder than bone conduction this is sensorineural hearing loss.
Non-eponymous signs and tests
Abdominal pseudohernia - bulging on one side of the abdomen due to weakness of the muscles at that myotomal level rather than a true hernia. Causes include VZV (including without a rash - i.e. sine herpeticum), Lyme and herniated discs, which are uncommon in thoracic regions.
Abulia - a state of apathy and inertia. People are awake, alert and responsive, yet say little, initiate little without prompting and make few movements. It's associated with damage to the cingulate gyrus in the medial brain, and can be seen with anterior circulation strokes or as a complication of anterior communicating artery aneurysm rupture.
Acalculia - loss of ability to work with numbers and perform simple arithmetic. Associated with parietal lobe damage, particularly on the left - and can be part of Gerstmann's syndrome.
Action myoclonus - involuntary myoclonic jerks during voluntary actions such as reaching for an object, walking or standing still. Causes include drugs, metabolic disturbance, hypoxic brain damage, genetic and neurodegenerative disorders.
Agraphaesthesia - inability to recognise numbers or letters written on the palm (from the patient's perspective - the examiner needs to write upside down!)- in the absence of primary sensory loss. A cortical sensory deficit due to parietal damage.
Alexia without agraphia - inability to read, but with preserved ability to recognise letters, and with intact writing ability. The patient can read words slowly, letter-by-letter, spelling them aloud then sounding out the individual phonemes ('C-A-T - cat'). The usual cause is a form of disconnection syndrome due to corpus callosum damage separating the hemispheres. The left occipital lobe is damaged, causing right homonymous hemianopia, and there is additional damage to the splenium of the corpus callosum. Visual information from the left hemifield still gets to the right occipital lobe, but information for words cannot be transmitted over to the left hemispheric language centres. /
Allaesthesia - ipsilateral sensory information is perceived as if on or from the other side. Parietal dysfunction is the major cause.
Anisocoria - asymmetrical pupil sizes. This has many causes. In unconscious patients the main concern is life-threatening uncal herniation causing an oculomotor palsy.
Anosoagnosia - lack of awareness of a deficit. Examples include visual field defects the patient hasn't noticed as primary loss of vision, but instead notices the consequences (e.g. bumping into things) - the most extreme example being Anton-Babinski syndrome (complete lack of awareness of blindness, with confabulation of vision). Another is lack of awareness of, or concern about, a weak limb.
Anterocollis - a pattern of cervical dystonia in which the neck is flexed
Applause sign - inability to clap only three times when asked to. The patient continues to clap beyond three times. This is a marker of frontal lobe dysfunction and is a form of perseveration. It is mainly used in distinguishing Parkinson's disease from atypical mimics such as progressive supranuclear palsy and corticobasal syndrome, which both feature frontal lobe dysfunction.
Astereognosis - inability to work out what an object held in the hand is, such as a coin or pen. This is despite primary loss of sensation (the hand is not numb) - and without loss of actual knowledge of what this object is (the patient would otherwise recognise it, e.g. by vision or hearing its name). A cortical sensory deficit due to parietal damage.
Apraxia - issues performing a task that are not otherwise explained by any of the following - weakness, numbness, ataxia, confusion/cognitive impairment or other more 'primary' issues. Instead it's best thought of as a problem with complex performance of tasks, due to failure of parts of the brain involved in generation an action. Apraxia has various types, and they're often seen in neurodegenerative disorders. Subtypes include
Astasia - inability to stay upright in the absence of primary weakness in the legs. Often seen in functional disorders, along with abasia (inability to walk)
Asterixis - inability to maintain a static position, with tone being lost, then a myoclonic jerk to resume the initial position. This is best seen with outstretched hands. In various encephalopathies it can be seen, for example hypercapnoea, uraemia, or hyperammonaemia. It can also be seen unilaterally with brain damage, for example from stroke.
Autonomic dysreflexia - a complication of spinal cord lesions. When a hollow viscus (usually the bladder) is distended, or there is an injury below the lesion (such as soft tissue infection or ingrown toenail), the patient develops severe hypertension accompanied by flushing and bradycardia. Headache is also common.
Bovine cough - a weak, breathy and non-explosive cough caused by vocal cord weakness. Particularly linked to vagus nerve pathology, especially the recurrent laryngeal nerve with lung apical (Pancoast) tumours - though another cause is lateral medullary damage.
Camptocormia - axial dystonia leading to the torso being bent at the hips, making walking very difficult, but unlike fixed disorders such as kyphosis, when the patient lies down the posture straightens. A sensory trick to help this is wearing a backpack. Can be seen in Parkinson's and other similar diseases.
Carotid bruit - auscultating the carotid at the jaw angle may hear a bruit, due to turbulent flow. This could reflect carotid stenosis, though often is due to other factors, and many people with carotid stenosis do not have an audible bruit - so the sign is neither sensitive nor specific and adds little. If you suspect carotid stenosis, get an ultrasound or CT angiogram.
Cerebral polyopia - seeing more than one image, not because of a lens problem (monocular diplopia) nor eye alignment problems (binocular diplopia) but originating from within the brain itself. The patient sees two images then with one eye closed still sees two - and swapping to the other eye, still sees two.
Chemosis - redness and swelling of the conjunctiva. There are many causes beyond the realm of neurology - our main concerns are in the cavernous sinus, namely thrombosis and carotid-cavernous fistula.
Circumduction - spastic weakness in a leg causes plantarflexion, lengthening the leg, as well as weak dorsiflexion, knee and hip flexion. In patients who can still weight bear (i.e. are not hemiplegic), they cannot lift the leg off the ground high enough to clear the foot, so instead they lean their torso to the intact side, and swing the leg in an arc out to the side. Then they plant it and shift their weight back to the centre. There is also typically evident spasticity in the arm, which is held in a flexed posture with a clenched fist.
Claw hand - a characteristic deformity seen with ulnar nerve lesions, affecting the ring and little finger. The cause is lumbrical weakness. The lumbricals flex the metacarpophalangeal joints (MCPJs) while holding the interphalangeal joints (IPJs) extended. In health, a neutral position exists due to tonic activity in the lumbricals and forearm muscles which affect finger position. Lumbrical weakness causes MCPJ extension and IPJ flexion. More proximal damage at the elbow affects the ulnar branch to the flexor digitorum profundi muscles, so the flexion is abolished and the fingers are straight. This more extensive lesion looks less dramatic on clinical inspection (weakness is more extensive but deformity is less), termed the ulnar paradox.
Cock-walk gait - dystonic hyperactivity in the calf muscle causes a pattern of walking on the toes. This is different to foot drop, in which dorsiflexion weakness causes the distal foot to hang down, with the patient taking high steps to compensate, and placing the entire foot down instead of just the toes. Cock-walk gait is best-known in association with disorders of manganese accumulation - whether exogenous toxic exposure (e.g. in welders) or an endogenous gene error leading to brain deposition.
Collapsing weakness - a limb initially has full power then gives out, dropping with gravity - almost like a sudden power-cut. A functional pattern - though pain will also lead to this as people struggle to make or sustain maximal effort. It's not a pattern seen with organic causes of weakness.
Confusion - a very common problem, yet an imprecise term! It's used to mean almost any presentation of ‘not acting normally’ or ‘altered mental status’, but can reflect many different problems, some of which, ironically, don't really cause confusion but simply hamper communication (and if people could speak, they'd otherwise be found to be completely cognitively intact). Problems may be due to amnesia, disorientation, aphasia, drowsiness, apraxia, psychosis, intermittent periods of loss of awareness (for example with seizures) and many more disturbances that affect one's ability to think and communicate clearly and interact normally with the world.
Convergence spasm - a functional sign seen on eye movement testing. The eyes converge, and the pupils constrict. The patient loses fixation and reports diplopia. It's important to distinguish this from bilatetal abducens palsies.
Cortical blindness - bilateral (both hemifield) and binocular visual loss due to bilateral occipital lesions. Patients often are not aware of the visual loss (Anton-Babinski syndrome). Causes include progressive multifocal leukoencephalopathy, posterior reversible encephalopathy syndrome, Creutzfeldt-Jakob disease (Heidenhain variant) and bilateral strokes.
Cortical myoclonus - myoclonus driven by a cortical signal. This is usually focal, and often induced by action (e.g. reaching).
Decorticate posturing - involuntary posturing (arms flex, legs extend) seen with brain damage. When this happens as a reaction to stimuli it is scored a 3 on the motor component of the Glasgow Coma Scale.
Decerebrate posturing - involuntary extensor posturing (arms extend and internally rotate at the shoulders, legs also extend) seen in people with coma and severe brain damage, including the red nuclei (and abolishing the rubrospinal tracts). When this happens as a reaction to stimuli it is scored a 2 on the motor component of the Glasgow Coma Scale. The only thing worse is no reaction whatsoever.
Dermatochalasia - the upper eyelid skin drops in a fold over the eye. Distinguish this from true ptosis by the lack of visible upper eyelid crease and the absence of eyelashes in the skin fold (it's not the true edge of the eyelid!)
Diphasic dyskinesia - a type of levodopa-induced dyskinesia seen in a minority of patients' with Parkinson's disease. Diphasic dyskinesias are involuntary hyperkinetic movements seen in the transitional phase when levodopa doses are absorbed then again when they wear off - i.e. on either side of the slope of the sine wave. This is different to peak-dose dyskinesias, which are much commoner. The movements are mainly in the lower limbs, and are commoner in younger patients.
Disinhibition - more of a behavioural tendency than an individual sign, but in general this reflects loss of ability to suppress normal impulses and instincts due to frontal lobe dysfunction. It might manifest in apparent rudeness (insensitive remarks, interruptions, or open admissions of boredom) as well as other behaviours such as impulsively picking items up or wandering around. Other forms may be apparent in the history, for example sexually disinhibited behaviour.
Disorientation - loss of awareness of where one is, who others are (and sometimes oneself though uncommonly), the time, and recent events.
Dissociated sensory loss - loss of one sensory modality with preservation of another. This is particularly seen with loss of pain and temperature sensation but preserved touch, vibration and proprioception, and it's not always obvious from the history unless you ask (e.g. showers, hot water while washing dishes) - so it's worth testing the different sensory modalities to look for it. Important causes include lateral spinal cord damage and lower brainstem damage - affecting the spinal trigeminal nucleus and its tract below their reunion with the other trigeminal sensory neurons.
Drowsiness - a state of reduced consciousness in which the patient is reusable but requires repeated and sustained stimuli to maintain interaction and alertness, or else they ‘nod off’.
Dysarthria - slurring of words (an issue with articulation). When the slurring is so severe as to make speech incomprehensible, this is anarthria. This is distinct from dysphasia which is a language issue, not a speech one.
Dysdiadochokinesis - rapid alternating movements (tapping the palm, then dorsal hand, then palm again on repeat) are messy and uncoordinated rather than smooth and clearly demarcated. A sign of upper limb ataxia, and the most difficult word to pronounce in neurology.
Dysmetria - missing a target, whether by overshooting (hypermetria) or undershooting (hypometria). When this applies to a hand reaching out, as in the finger-nose test, we speak of 'past-pointing'. It can also be shown with saccadic eye movements.
Dysphasia - impaired language ability. This presents with issues related to verbal (word-based, not specifically 'spoken'!) communication. There may be issues with speaking/writing/typing (expressive dysphasia), or understanding speech or written words (receptive dysphasia). If both are present this is 'mixed dysphasia'. Various subtypes exist depending on the impact on abilities including overall fluency, naming, repetition and comprehension.
Dystonia - involuntary muscle contraction leading to abnormal postures which are often twisted. There may be jerky tremulous movements.
Echopraxia - copying others' gestures or actions. Seen in autism in particular.
Exodeviation - the eyes deviate outward (divergent squint). Esodeviation is the opposite..
Facial diplegia - bilateral lower motor neuron facial palsies. It has many causes, including various immune and infective disorders, and central pontine tegmentum lesions (usually with other features such as horizontal gaze paresis to one or both sides).
Fatiguable weakness - repeat or sustained activity in a muscle causes progressive weakness. A sign of neuromuscular junction disease. Different to collapsing weakness - which is more like a sudden ‘power cut’ and is a functional sign.
Femoral stretch test - provocative manoeuvre for radiculopathy in the L2-L4 region. It's like the straight leg raise test (for L5-S1) but the patient lies on their front. The examiner passively extends the hip. If symptoms are reproduced this is positive.
Fencing response - posturing with one arm extended and the other flexed, similar to the posture seen in fencing. Happens during sudden head trauma, but can also be seen in frontal lobe seizures, particularly those originating in the supplementary motor area.
Figure 4 sign - a posture adopted during focal seizures, usually frontal lobe origin. The ipsilateral arm is flexed across the body while the contralateral arm is extended - resembling a 4.
Finger agnosia - difficulty knowing which finger is which - e.g. pointing at the wrong one when asked to point at a particular finger. Part of Gerstmann's syndrome, with left parietal damage.
Floccilation - the random picking at clothing and sheets seen in delirious patients.
Freezing of gait - pauses in walking, particularly through door frames, in narrow spaces (such as between furniture) or when transitioning from a carpet to bare floor. Walking resumes after a number of small steps on the spot, although there are numerous ‘tricks’ that help patients start walking. Seen in parkinsonian disorders, often associated with cognitive impairment.
Gaze preference - a tendency to only look (with both eyes) to one side of the world. This may be forced, whether due to failure of a unilateral gaze centre (for example in stroke) or over-activity of another gaze centre (as in seizure) - but it may also reflect other factors such as neglect, in which the patient simply favours one side - rather than the eyes being forcibly pushed to it.
Gelastic seizure - a seizure featuring laughing, associated with hypothalamic hamartomas.
Geste antagoniste - a 'sensory trick' done by patients to temporarily relax or suppress a focal dystonia, for example stroking the neck (cervical), or touching the eyelids (blepharospasm).
Head drop - the head rests in a lower and more anterior position than normal due to either weakness in the extensors (e.g. from myasthaenia) or increased action in the flexors (antecollis - a type of cervical dystonia).
Head-turning sign - the tendency of someone with cognitive impairment (particularly Alzheimer's) to turn to the person accompanying them for answers, including the basic opening question around why they have come to the doctor today (which, incidentally, was usually the accompanying person's idea).
Hippus - spontaneous fluctuations in pupil diameter, constricting and then dilating. This can be beign though can be seen in other conditions such as seizures (especially occipital).
Hung-up myoclonus - slowly relaxing muscles after a myoclonic jerk. Characteristic of subacute sclerosing panencephalitis (measles virus reactivation years after primary infection).
Hung-up reflexes - slow relaxation of reflexes. Seen in chorea (e.g. Huntington's) and also hypothyroidism.
Hypoalgesia - diminished but present pain sensation, which can be seen on pinprick testing. The patient detects it and can feel it as a sharp sensation (in contrast to analgesia) - it just feels less sharp than it normally would, which is most obvious when another region has normal sensation.
Hyperekplexia - we all have a startle response to a sudden and sufficient stimulus. It has a pattern in terms of flexion of various body parts. If it is excessively pronounced, happens relative to minor stimuli (e.g. the examiner clapping), and doesn’t habituate, and causes a profound increase in muscle tone (capable of producing falls) - this is hyperekplexia. There is also a genetic disorder termed hereditary hyperekplexia which causes a familial form of this.
Ice pack test - ptosis due to neuromuscular junction weakness, as seen in myasthaenia gravis, improves after an icepack is placed on the affected eyelid for several minutes. This isn't a test to bring out latent ptosis - it's to see if ptosis improves or not. If it does, it suggests myaesthaenia.
Inattention - When there are bilateral stimuli presented, only one is detected - the stimulus to the intact side of the brain extinguishes the other. In this situation there is no primary deficit in sensation itself - e.g. hemianopia - and a unilateral stimulus can be detected in the field that has inattention. It's only when bilateral stimuli come that the patient cannot detect one side. This applies to vision and touch, which are represented on one side of the brain only. It doesn't apply to sound, which has bilateral brain representation from each ear. Neglect is a related term but refers more to the syndrome or behaviours seen as a result - effectively 'ignoring' half of the world.
Inverted reflex - tapping a tendon does not elicit the usual reflex, as it is absent - yet paradoxically the antagonist muscles react and move the joint in the opposite direction. This happens due to hyperreflexia in the antagonist. It is seen with LMN damage at the reflex being tested, and UMN damage below it - e.g. tapping the biceps (C5) leads to triceps contraction (C7) - due to spinal cord damage, often involving the ventral root (as in myeloradiculopathy). Another example is the inverted supinator reflex - the supinator (really, this is the brachioradialis) reflex is absent on testing but the signal causes finger flexion (C7/C8).
Junctional scotoma (of Traquair) - a lesion anterior to the chiasm compresses the incoming optic nerve as well as the anterior chiasm where fibres are crossing from the temporal visual field in the other eye. This crossing is organised such that the superior quadrant crosses anteriorly while the inferior crosses posteriorly. The effect is ipslateral central visual loss due to right optic neuropathy and contralateral superior temporal quadrantanopia due to compression of the crossing fibres.
La belle indifference - lack of apparent concern regarding a neurological problem such as paralysis of one side or seizures. This was traditionally thought to be a marker of a functional or deliberately feigned condition. The problem with this is that it isn't reliable:
While it has no diagnostic value, it is still important: if a disorder is diagnosed as functional (using reliable measures), the presence of La belle indifference should be addressed, as it can be a barrier to rehabilitation, and probably reflects a dissociative reaction to traumatic experiences that may benefit from support.
Lateropulsion - a tendency to fall or lean to one side. This may be to the side of the lesion - with cerebellar disease - or away from it, with pyramidal weakness above the pyramidal decussation. The difficulty is, peripheral vestibular lesions can also cause it, so caution should be used if using it as a presumed sign of a central lesion in acute vertigo.
Macular star - a star-shaped array of white spots filled with lipids seen on the retina, encircling the fovea. A sign of neuroretinitis due to cat-scratch disease from Bartonella henselae infection.
Magnetic gait - short steps are taken with a broad stance, and the feet shuffle, barely leaving the ground - as if the patient is stuck down. Sometimes termed gait apraxia though this term is disputed. The classic cause is hydrocephalus, particularly normal pressure type.
Marche a petit-pas - Short steps are taken with increased arm swing. Said to be a marker of vascular parkinsonism - which is a debated entity.
Midline sensory splitting - sensory loss from head to toe in an entire half of the body, suddenly normalising beyond the midline. This is often a functional problem, though thalamic lesions can produce this.
Milkmaid's grip - a pattern of motor impersistence seen in chorea. The patient cannot sustain grip, so it temporarily releases then resumes squeezing - similar to milking a cow's udder.
Miosis - excessive pupil constriction. Some important causes include Horner's syndrome (sympathetic chain damage) and, if bilateral, pontine lesions. Drugs are also important - especially opiates.
Motor impersistence - inability to maintain a position, seen with chorea. Examples include inability to keep the tongue stuck out the mouth, or the 'milkmaid's grip' (intermittent squeezing and relaxing during gripping).
Mydriasis - excessive pupil dilatation.
Myoclonus - shock-like jerky movements in part of the body. These may be spontaneous, triggered by movement (action myoclonus), or be seen as inability to hold a posture with a sudden drop (negative myoclonus). It may be induced by touch or noise (stimulus-sensitive myoclonus). Many different types exist, classed by the presumed site of origin (e.g cortex or brainstem), with different patterns.
Neglect - in the absence of a primary sensory or motor deficit (e.g. hemianopia or paralysis) the patient doesn't seem to do anything involving the side of the world contralateral to a damaged hemisphere. Examples are not moving a limb, or not interacting with objects in that hemi-space. They may also have a gaze preference to the other side. They will generally display inattention when bilateral stimuli are given - visual or tactile - only perceiving the one going to the intact hemisphere; physically this stimulus will be on the same side as the lesioned hemisphere - generally the right.
Nystagmus - repetitive movements of the eyes. They are not random but repetitive. The commonest pattern is jerk nystagmus with a slow drift off the target followed by a corrective saccade back to the original position. The direction of the saccade ('beating') defines the direction of the nystagmus - for example, right-beating or down-beat nystagmus. In this situation the slow phase There are many different types of nystagmus:
Brainstem reticular myoclonus - a characteristic pattern of myoclonus, spreading in a specific sequence, often induced by stimuli such as touch or startle.
Ocular bobbing - periodic down and in movements of both eyes, then slow return back up and out. Seen with brainstem damage, usually also featuring unconsciousness. The movements are less frequent than downbeat nystagmus.
Ocular flutter - horizontal rapid movements from side to side with no inter-saccadic interval. Similar to opsoclonus but only in the horizontal plane. Can be paraneoplastic.
Ocular tilt reaction - central vestibular system damage affects the patient's sense of lateral tilt - in the primary position with a neutral head their system feels as if it is leaning to one side. The eyes adopt the position they would if this was the case - one up and intorted, the other down and extorted - and they lean to the other side (as if compensating for a tilt). If the head were tilted right, the left eye would be up and intorted, the left down and extorted. The key pathway crosses, so this doesn't lateralise exclusively (unlike, say, Horner's) - but it can be cross-localised if other features co-occur.
Onion skin sensory loss - the spinal trigeminal nucleus is unusual; it drops as far as C4 before the fibres cross and rise in the ascending tract. The nuclear parts and fibres are somatotopic, and differ from the usual V1-3 trigeminal arrangement (seen in peripheral nerve lesions). The lowest parts of the nucleus and the lowest fibres convey sensory information from the outer face, and those higher up carry information that eventually includes the nose and mouth. Low lesions may leave the central parts intact, similar to a balaclava.
Opisthotonus - back arching with the neck extended, lifting the body off the ground, supported by the head and feet. Seen in tetanus but also a marker of functional (dissociative, or non-epileptic) seizures.
Optic atrophy - a late complication of optic nerve damage. The nerve head atrophies, becoming pale and white. The margin looks very sharp - the opposite of papilloedema (optic nerve head swelling due to high CSF pressure) where it is blurred. Causes include optic neuritis, compressive tumours, ischaemic damage and genetic conditions.
Optociliary shunt vessels - chronic retinal venous obstruction causes collaterals to open up, visible as tortuous and thick vessels on the optic disc. They can be suggestive of optic sheath meningioma - when they are seen along with optic atrophy and optociliary shunts this is very suggestive.
Opsoclonus - 'dancing eyes' or 'saccadomania' - rapid and random lightning-like jerky movements of the eyes, often triggered by eye movement. In many ways its like myoclonus of the eyes. Unlike nystagmus there is no inter-saccadic interval. The major condition liked to it is opsoclonus-myoclonus syndrome, which can be inflammatory or paraneoplastic.
Pallilalia - the person repeats words or syllables already said by them, like an echo, each word quietening. Various causes exist for this including neurodevelopmental conditions (autism, Tourette's) but it can be seen in some degenerative disorders such as progressive supranuclear palsy.
Papilloedema - optic nerve head swelling due to raised intracranial pressure (ICP). The optic nerve is part of the central nervous system (CNS), and is surrounded by arachnoid matter, with cerebrospinal fluid (CSF) in this subarachnoid space, continuous with the CSF space around the brain. Papilloedema is a helpul clue to raised ICP. It's nearly always bilateral bar some unusual situations, for example optic atrophy in the other eye (Foster-Kennedy syndrome). We can't say someone has papilloedema until we prove raised intracranial pressure, because optic nerve head swelling from other causes (ischaemia, inflammation) can look exactly the same - so we either need to perform a lumbar puncture, or show an intracranial lesion on imaging that would cause high ICP.
Parakinesia - - a tendency of patients with chorea to disguise the movement as a natural action, e.g. looking as if tying a shoelace, wiping hair or hand rubbing. This is often unconscious - many with chorea, unless acute onset, have anosoagnosia (lack of awareness of the problem), particularly if there is also cognitive impairment, as in Huntington's.
Paralytic pontine exotropia - a pattern of abnormal eye movements seen with unilateral lesions in the dorsal caudal pontine tegmentum. There is a one-and-a-half syndrome (ipsilateral conjugate gaze palsy looking to the side of the lesion, and internuclear ophthlamoplegia looking away from it) - the eye on the side of the lesion cannot abduct or adduct during attempted horizontal gaze to either side. Convergence is intact however. The eye on the opposite side rests in an exotropic (turned out) position.
Paroxysmal dysarthria-ataxia - a disorder associated with lesions in the cerebello-rubro-thalamic tract, particularly in the caudal paramedian midbrain. Patients have recurrent attacks of dizziness, altered balance and inability to speak normally - they are not dysphasic but struggle to move their tongue and are dysarthric. The attacks last seconds, resolve rapidly with no aftermath, and are not epileptic but due to ephaptic transmission. The main cause is multiple sclerosis but others include stroke and Behcet’s.
Pendular reflex - in cerebellar disease, if the patient is sat with the leg dangling, then when the patellar reflex is tested the leg will kick out, swing back, and swing back and forward a few times before stopping. While this is described as a marker of hypotonia, it isn't always present.
Percussion myotonia - myotonia - abnormal muscle contraction which is sustained, with slow relaxation - can be induced by tapping a muscle, for example the thenar eminence (causing the thumb to abduct). Seen in myotonic dystrophy.
Perseveration - continuing to perform an action after an instruction has ceased or the interview has moved on - for example, repeatedly sticking the tongue out after being told only to once, or continuing to talk about a topic as the assessor tries to change to another. Seen in various cognitive disorders including acute encephalopathies and fronto-temporal dementias.
Pes cavus - abnormally high arches in the feet. Associated with genetic neuropathies, particularly Charcot-Marie-Tooth disease, and also congenital cauda equina disorders such as spinal bifida.
Polyminimyoclonus - frequent, small amplitude, random and non-rhythmic jerking of the fingers, best seen with hands and fingers held straight. Associated with conditions such as multiple systems atrophy. Easily mistaken for tremor, which is organised, repetitive, rhythmic and around a fixed axis.
Propriospinal myoclonus - jerking movements of the trunk, causing flexion, sometimes during the sleep-wake transition. The jerks may be stimulus-sensitive. While it can be seen with structural lesions (e.g. spinal), it often is functional (psychogenic). EEG can show a pre-jerk negative deflection (Bereitschaftpotential) suggesting that - at least unconsciously - this jerk is under voluntary control.
Pseudo-abducens palsy - inability to abduct the eye but not due to a VI lesion. The problem is supranuclear (often thalamic) so the eye can still abduct on oculocephalic reflex testing.
Pseudoathetosis - involuntary writhing movements of the limbs which are maximal when the patient is not looking at them or the eyes are shut. A sign in severe sensory ataxia, usually due to sensory neuronopathy (dorsal root ganglionopathy)
Pseudobulbar affect - a tendency to emotionally labile reactions to minor stimuli that wouldn't normally evoke these, particularly at earlier (premorbid) times in this person's life - for example laughing or crying easily, often both in short succession. Associated with bilateral frontal lobe damage, particularly in motor neuron disease or bilateral strokes.
Pseudobulbar speech - a form of spastic dysarthria due to bilateral upper motor neuron damage. The tongue is stiff and slow and speech is very laboured.
Ptosis - drooping of one or both eyelids. This has many causes.
Pyramidal weakness - the upper limb flexors are stronger than the extensors, and in the lower limbs the opposite is true. In paresis (but not plegia) of these limbs, this pattern is preserved - flexor and extensor muscles both are weakened, but one is more so than the other - so flexion is relatively preserved in the arms, and extension in the legs. This is not seen in lower motor neuron weakness. However the reliability of this is debated.
Reflex spread - UMN damage makes muscles hyper-reactive, and tapping a reflex may cause adjacent muscles to also contract as if the reflex has ‘spread’ or 'spilled over' into its neighbours - e.g. finger flexion (median, C7) when the brachioradialis (radial, C6) is tapped.
Rhinolalia aperta - hypernasal speech. In neurology it suggests palate weakness, and causes include myasthenia, botulism and some cases of the Miller-Fisher variant of Guillain-Barre syndrome.
Rocker-bottom foot - a complication of sensory neuropathy. The arch collapses and tarsal bones are now load bearing on the floor. This can lead to pressure damage and ulcers. If those get infected a world of trouble follows. Prevention is key - podiatrists work miracles. It's far harder to control an established ulcer than it is to prevent one.
Rocket sign - people with progressive supranuclear palsy (PSP), a neurodegenerative condition, often have frontal lobe impairment, leading to impulsivity. This is accompanied by impaired balance and frequent falls (usually backwards). The rocket sign is seen when patients are asked to stand up and demonstrate walking: they rapidly rise from the chair or bed, and often fall backwards immediately after.
Saccadic contrapulsion - involuntary hyperkinetic movements seen in the transitional phase when levodopa doses are absorbed or wear off - unlike peak-dose dyskinesias, which are much commoner.
Saccadic dysmetria - we can normally generate a saccade to a target we see in the periphery; the eyes move the right amount - no more or less - to reach fixation. If saccades are hypo- or hyper-metric they under- or overshoot respectively. This can be seen in cerebellar damage (particularly the central structures such as the vermis or fastigial nucleus).
Saccadic intrusion - brief saccades during static eye fixation on a target, disrupting focusing. Seen in a range of cerebellar disorders, including genetic ataxias and drug toxicity states.
Scapula alata - a winged scapula. The medial scapular border appears prominent, particularly with the arms outstretched as if pushing forward, due to weakness of the muscles that hold it in place. Depending on the nerve and muscles involved the pattern varies:
Scissor gait - spasticity affecting both legs (diplegia) causes hip adduction tightnight which pulls the femurs toward each other, meaning the knees are in contact, then below them the tibias diverge and the feet are apart. The overall shape is X-like, resembling scissors.
Scotoma - an area of blurred or absent vision with surrounding vision intact. It can be central, obscuring the main focal point, as is seen in optic neuritis. It can also be arcuate, forming an arc in an area off-centre, seen in glaucoma (due to damage to nerve fibres in the retina)
Sectoranopia - a defect in only part of one hemifield, but crossing the horizontal meridian to involve both quadrants. This can happen with lateral geniculate damage. The classic cause is an anterior choroidal artery infarct - which also features hemiplegia and hemisensory loss due to damage to the nearby capsular fibres.
Sensory ataxia - loss of proprioceptive input impairs the brain's ability to know where part of the body is. This causes impaired coordination, particularly in the absence of visual input. The result is a tendency to lose balance in the dark, or when upright with eyes closed, for example when showering - and this is the basis for the Romberg's test. Key causes include dorsal root ganglion pathology (for example paraneoplastic syndrome) and dorsal column disease.
Simultagnosia - inability to see an overall scene, despite ability to see its components - ‘missing the forest for the trees’. A higher-order visual processing issue due to parietal dysfunction. Part of Balint's syndrome, though the full triad is probably rare.
Somatoparaphrenia - delusional belief that a paralysed limb (or side of body) is not the patient's but is in fact someone else's - so not just neglect, but full awareness of the limb as if it's another person's.
Spasmodic dysphonia - a high-pitched straining quality in the voice due to tightness of vocal cord muscles. Treatable with botox. This can be a sporadic and isolated problem though can be seen in neurodegerative disorders.
Split hand - a pattern of disproportionate wasting in the thenar eminence (radial side of the palm) compared to the hypothenar (ulnar) side, seen in motor neuron disease.
Stage curtain sign - due to a unilateral vagus (X) nerve lesion - drooping of the palate on the affected side, with deviation of the uvula away from it. Not to be confused with the curtain sign in myasthaenia!
Start hesitation - difficulty initiating gait. The person feels as if stuck down and can take small steps on the spot but not start moving forward. Certain tricks can help, like counting. Seen in Parkinson's, usually at the more advanced stages, and other related conditions such as progressive supranuclear palsy.
Steppage gait - the swing phase of gait involves the leg going forward, and a certain amount of dorsiflexion avoids the foot scuffing the ground. Dorsiflexion weakness causes foot drop, so to compensate the patient lifts the leg at the hip and knee. The foot tends to slap down noisily on the floor, so this is also called a slap gait.
Strabismus - a squint; the eyes are not aligned normally. This can be seen as a developmental issue but can be aquired, for example through nerve palsies.
Striatal hand - deformed hands due to Parkinson's, with flexed metacarpophalangeal and extensed interphalangeal joints, which can resemble rheumatological disorders but is actually due to dystonia.
Striatal toe - dystonia in the leg leads to the great toe being stuck in a dorsiflexed position. Seen in Parkinson's.
Supranuclear gaze palsy - Inability to voluntarily look in a particular direction - yet the eyes can be directed in that direction via other means, unlike in a nuclear or infranuclear (fascicle or nerve) palsy where the movement cannot be generated at all. The main method to check this is to get the patient to fixate on a target and then passively move their head - the oculocephalic reflex allows the eye to move within the head, keeping its position on the target.
Suspended sensory loss - an area of the body has sensory loss, but sensation above and below this is intact. Central cord lesions can cause this, affecting sensory fibres entering the cord and passing through the centre at the affected levels. The classic cause is syringomyelia - with a cape-like distribution over the lower cervical dermatomes.
Synkinesis - as a facial palsy heals, there may be cross-wiring of branches, meaning that movement in one branch of the nerve stimulates movement in another. This is particularly seen with facial movements such as chewing or speech triggering blinking.
Tactile anomia - inability to name an object held in the left hand, despite ability to name it if in the right hand, and knowledge of what it is. There is no primary sensory deficit, nor is there astereognosis - if the object is placed among two others, the patient can identify it with eyes closed as the same one they held before. Happens in split-brain (disconnection) syndromes with corpus callosum damage: the right brain receives the left hand's sensory information, and the object is recognised - but the corpus cannot carry the information to the left hemispheric language centres for naming. There is no issue if the object is held in the right hand - the primary sensory information gets to the left hemisphere without the corpus being needed.
Thalamic aphasia - a form of mild expressive dysphasia seen with thalamic lesions. People are less fluent, and have intermittent word-finding difficulties, but it is far milder than Broca’s aphasia. Comprehension is intact as is repetition. The thalamus has extensive relations with the cortex, so lesions have many effects and can mimic what is seen in cortical damage.
Thalamic astasia - impaired postural control after thalamic damage, usually stroke. The thalamus is a major relay for sensory information concerning posture, including from the vestibular and cerebellar system.
Thalamic esotropia - in- and downward eye deviation. Also known as the 'peering at your nose' sign. Probably due to loss of inhibition of pathways involved in convergence.
Tic - a movement or vocalisation that is not quite involuntary - it can be resisted, but only for so long, with an urge building up - and is stereotyped. Tics can be simple or more complex (e.g. movements involving several joints). Tourette's syndrome is a developmental, lifelong condition featuring multiple types of vocal and motor tic.
Tightrope-walker gait - during tandem gait testing, ataxia causes people to simply step laterally 'off the line'. There is generally very little swaying - they just can't stay on the line. In contrast, a functional pattern of imbalance resembles a high-wire artist, often swaying dramatically, standing on one leg - which actually demonstrates excellent balance.
Titubation - a tendency to make head nodding movements while standing still, seen in truncal ataxia , usually accompanied by a broad-based stance and gait
Transient visual obscurations - temporary dimming or darkening of vision on standing, getting up from bending over (e.g. tying laces), or head/eye movement. Associated with high intracranial pressure and papilloedema.
Tremor - rhythmic involuntary movement around an axis. Further classified by the muscles involved and when the tremor happens - resting, static posture or on movement (including on approach to a target - intention tremor)
Utilisation behaviour - in frontal lobe damage, people tend to pick up and start using items in front of them. This is a form of disinhibition - we normally can resist this urge to pick up and utilise random items, particularly when visiting a doctor's office.
Visual agnosia - inability to recognise or make sense of an object seen, despite intact vision, and with knowledge of what the object actually is. If it were named aloud, the person would know what it is, and could describe its function. Tactile information (holding the object) would also allow this.
Visual anomia - inability to name an object seen - yet preserved ability to describe it, and knowledge of what it is. If touched, it can be named. Another name is optic aphasia/
Walking-on-ice gait - a functional gait disturbance in which people take small steps whith feet barely leaving the ground and a stiff, braced, cautious posture. The stance is narrow, unlike in ataxia.
Waddling gait - hip girdle muscle weakness in the context of myopathy makes hip abduction weak. We need this to stay upright on one leg - the torso is pulled toward the planted leg to counteract falling to the side of the elevated leg. When bilateral hip abductors are weak, the patient can only stay upright while walking by leaning the torso over the planted leg, then the other way as the other leg is planted, leading to a waddling, side-to-side torso pattern. While this might sound tiring, it's actually an efficient, natural compensatory pattern many patients adopt.
Wing-beating tremor - frequent, small amplitude, random and non-rhythmic jerking of the fingers, best seen with hands and fingers held straight. Associated with conditions such as multiple systems atrophy. Easily mistaken for tremor, which is organised, repetitive, rhythmic and around a fixed axis.
Witzelsucht - tendency to make jokes and puns, seen in people with frontal lobe damage, particularly the right orbitofrontal cortex. People with frontal lobe impairment often can seem inappropriately jocular, but this is an extreme form.
Syndromes
There are too many of these to include, and many cause global or multi-site problems - so this is focused to anatomically-relevant ones from a localisation perspective. Many are eponymous so I've listed those, too.
Eponymous syndromes and diseases
While a number of these terms are no longer used widely they do still appear in some literature so are worth having listed here - but not necessarily memorised. In general I try to not use them if a more precise alternative exists - and if I do, I put them in brackets (e.g. 'lateral medullary syndrome (of Wallenberg)').
Relevant to localisation
The following reflect focal lesions. The much wider list of eponyms that are less relevant to localisation are given later...
Alice in Wonderland syndrome – complex higher-order visual dysfunction featuring a range of visual disturbances. Things may seem too close, far, big or small. When transient, repetitive and stereotyped, it can suggest occipital seizures.
Baanwarth syndrome – painful radiculitis due to Lyme disease. Sometimes associated with facial palsy.
Brainstem syndromes – there are many of these, describing collections of features due to lesions (particularly infarcts) at various levels and aspects of the brainstem. The exact definitions and features vary a little between sources. I prefer to just describe the features and lesion site, but these are still used by many. I've listed them in descending order, from midbrain to medulla:
Balint syndrome – a complex disorder of higher order visual processing due to bilateral parietal-occipital region damage (particularly the inferior parietal lobule). Three components:
The classic cause is bilateral borderzone (watershed) infarcts, and other causes include PRES, CJD and posterior cortical atrophy (a variant of Alzheimer's).
Baló’s concentric sclerosis - a neuroinflammatory disorder featuring a round, solitary brain lesion with a characteristic ‘onion skin’ appearance on imaging. It’s usually seen in young Asian men, and is a monophasic illness - even though it is often grouped as a variant of multiple sclerosis.
Bickerstaff’s brainstem encephalitis - a variant of Guillain-Barré syndrome, but unique in that it includes the central nervous system; it involves the brainstem, affecting consciousness. Features include encephalopathy, encephalopathy and areflexia, but there may also be ‘central’ signs such as upgoing plantars. Associated with anti-GC1b antibodies.
Broca’s aphasia – lesion in the inferior frontal gyrus. Severe, non-fluent, expressive dysphasia, with broken, agrammatical sentences, difficulty saying words, and frequent phonemic paraphasic errors – but retained comprehension.
Brown-Séquard syndrome - a lateral cord lesion produces ipsilateral weakness and loss of touch sensation, and contralateral loss of pain and temperature sensation. The corticospinal tracts already decussated higher up, the dorsal column tracts are yet to decussate in the medulla, and the spinothalamic tracts decussated on entry to the cord - hence this 'split' pattern of dissociated sensory loss.
Brown-Séquard in reverse - attacks of tonic motor spasms affecting the limbs on one side, with contralateral pain in the limbs on the other side. Seen due to lateral cord lesions; the mechanism is ephaptic transmission. Attacks may be triggered by movement. The name reflects the fact that it is a ‘positive symptoms’ version of what Brown-Sequard syndrome involves - patients may have co-existing Brown-Sequard syndrome but often do not.
Bruns' syndrome – attacks of vertigo, vomiting, headache and sometimes unconsciousness often provoked by head movement, due to blockage of the fourth ventricle by a mobile mass (tumour or infectious cyst) - a life-threatening problem.
Bruns-Garland syndrome – diabetic amyotrophy, or diabetic lumbosacral radiculoplexus neuropathy (DLRPN). A painful inflammatory disorder affecting the lumbosacral plexus, usually on one side, accompanied by weight loss. Features include weakness, wasting, numbness and reduced reflexes in innervated segments. The cause is vasculitis related to diabetes. Unlike the much commoner diabetic neuropathy (slow, length-dependent) this is often linked to good, rather than poor, diabetic control.
Call-Fleming syndrome - see reversible cerebral vasoconstriction syndrome (RCVS).
Charcot foot -chronic bony deformities seen in sensory neuropathy due to abnormal load bearing and fractures which are undetected by the patient, with abnormal bony healing. The main cause in Western countries is diabetes but any sensory neuropathy could cause this, and some spinal conditions also do. It was a key feature in the historical syphilis epidemic, linked to dorsal column degneration.
Charles-Bonnet syndrome - visual hallucinations in an area of visual loss. In brain lesions behind the chiasm these are confined to the affected hemifield. They may be simple - e.g. colours or lines - or complex, particularly people or animals. People often know these are not real and are not too bothered about them. .
Chiari malformation - excessive (>5mm) descent of the cerebellar tonsils through the foramen magnum. Different types exist, classified according to the presence of other features. Many Chairi malformations are completely asymptomatic though symptoms can include cough headaches, effects of associated syringomyelia (when it co-occurs) and sometimes problems such as downbeat nystagmus.
Cogan syndrome - vasculitis affecting the eyes (keratitis) and cochlea, causing visual and hearing loss with pain, eye redness and photophobia.
Collet-Sicard syndrome – a combination of palsies of the lowest four cranial nerves (IX-XII). The chief cause is carotid sheath pathology, particularly dissection, as these nerves all pass through that structure.
Dandy-Walker syndrome - congenital absence of the cerebellar vermis, causing an enlarged fourth ventricle, and in some cases hydrocephalus.
Dawson's disease - see subacute sclerosing panencephalitis (SSPE).
Dejerine-Roussy syndrome - hemibody pain and paresthesia on the opposite side from a thalamic lesion. The major cause is a stroke, and the symptoms emerge weeks and months later, although other lesions such as glioma can also cause this.
Devic's disease - neuromyelitis optica. An aggressive, anti-aquaporin 4 antibody-mediated disease which features disabling demyelinating episodes affecting the optic nerve, spine (typically longitudinally-extensive and thick lesions), parts of the brainstem (such as the area postrema) and sometimes deep brain structures such as the hypothalamus (causing narcolepsy). Formerly thought of as an uncommon MS subtype but modern understanding is that this is a very different disease, managed differently.
Elsberg syndrome - damage to the cauda equina and conus medullaris due to a virus, usually HSV2 although VZV can also cause this. Both can respectively feature genital or dermatomal vesicles, but may not. Symptoms include pain, weakness, sensory loss and sphincter disturbance. CSF often shows elevated lymphocytes and sometimes positivel viral studies (PCR or elevated antibodies).
Erb-Duchenne palsy – upper brachial plexus damage, usually congenital from birth injuries, causes paralysis of some muscles. The characteristic arm position is internally rotated, elbow straight, and the wrist partly flexed, so that the palm is upward - the ‘waiter's tip’ position.
Foix-Marie-Chavagny syndrome – The facial and oral muscles are innervated by lateral parts of the motor homunculus which are in the operculum. Bilateral opercular damage paralyses these for voluntary movements. However, emotions can still trigger movements in these muscles via alternative pathways - the amygdala and hypothalamus supply the brainstem through the medial forebrain bundle and dorsal longitudinal fasciculus. This is an example of voluntary-automatic dissociation
Foster-Kennedy syndrome – a meningioma causes elevated intracranial pressure, which would normally cause bilateral papilloedema - but also compresses the optic nerve on one side, so the result is one swollen and one atrophic disc. The full triad includes anosmia.
Gerstmann syndrome - a cluster of consequences of left inferior parietal lobule damage (affecting the angular and supramarginal gyri). The four features are agraphia, acalculia, finger agnosia and right-left disorientation.
Godtfredsen syndrome– combined unilateral VI and XII palsies, due to a skull base lesion in the clivus - often a tumour. This is also known as clivus syndrome.
Gradenigo syndrome - facial pain in a trigeminal distribution with associated VI palsy. Due to inflammation in the petrous apex of the temporal bone (petrous apicitis), a complication of ear infections. Uncommon nowadays.
Heerfordt syndrome – a presentation seen in sarcoidosis, with a trial of parotid gland inflammation (often bilateral), facial palsy (the nerve travels through the gland) and uveitis. There is usually fever, hence it is also called uveoparotid fever. It can mimic infection.
Heidenhain variant of CJD – a presentation of sporadic CJD with rapidly progressive visual disturbance, often hemianopia or frank cortical blindness but also higher-order visual disturbances (e.g. palinopsia, akinetopsia, macropsia) and visual hallucinations, usually followed quickly by typical features such as dementia, ataxia and myoclonus. This is usually seen with the MM1 or MV1 form of sporadic CJD and overall survival duration is typically a number of weeks.
Hirayama disease - a pattern of focal motor neuron disease (MND) affecting a single arm (i.e. monomelic), seen in young Asian males. Weakness rapidly develops, curiously sparing the brachioradialis - which becomes promiment due to atrophy in its neighbours. This is self-limiting and is not a neurodegenerative condition unlike most MND. One theory is that it is due to compression of the ventral horn on neck flexion, and some people recommend MRIs in flexion and extension.
Horner's syndrome - features due to disruption any one of the three sympathetic neurons in a long pathway from the hypothalamus through brainstem, cervical and upper thoracic spinal cord, sympathetic chain, cervical ganglia and eventual output to the face, including the pupil and eyelid. The consequence is a constricted pupil (with the anisocoria most visible in the dark), a partial ptosis, and loss of facial sweating (though this part can be subtle or absent). Horner's has many causes - what helps localise the lesion is other co-occuring features (e.g. those of Wallenberg syndrome, or other cranial nerve palsies).
Jacksonian seizure - a spreading pattern of epileptic activity within the motor cortex (precentral gyrus) causes tonic contractions in the contralateral face and body. As the seizure focus advances along the motor strip, the contractions affect additional segments. For example this may start as leg contractions then spread to involve the proximal arm, then hand, then face, mapping out the homunculus.
Jacod syndrome - orbital apex syndrome. The term is rarely used now.
Joubert syndrome - a genetic disorder affecting children, with cerebellar malformation. The superior cerebellar peduncles, connecting the upper pons to the cerebellum, are abnormally thick, causing the 'molar tooth sign' on axial MRI.
Klumpke palsy - damage to the lower trunk of brachial plexus, usually congenital from birth injuries, leads to weakness and wasting of intrinsic hand muscles, with clawing, and sensory loss. Horner's can be seen - in congenital cases the iris is blue
Klüver-Bucy syndrome - Bilateral amygdala and temporal damage leaves people with significant behavioural changes. They become docile, but also hypersexual, and with a tendency to hyperorality - putting objects in their mouth which are non-edible. Herpes simplex encephalitis is a classic cause, although similar features can be seen in frontotemporal dementia.
Leber’s hereditary optic neuropathy - a genetic disorder due to a pathological change in a mitochondrial gene (MT-ND1, -ND4 or -ND6), causing bilateral sequential subacute visual loss in each eye due to optic neuropathy. This is usually in young men, despite the gene not being on a sex chromosome, and can be triggered by smoking. The importance is remembering it when you assess potential optic neuritis cases. The visual loss is severe, and there is no pain.
Lemierre’s syndrome - Fusobacterium necrophorum infection - usually in teenage males - causes a severe illness featuring fever, sepsis, sore throat, jugular vein thrombosis (and often intracranial venous sinus thrombosis) and pulmonary infiltrates. The incidence is rising.
Lhermitte-Duclos disease – i.e. dysplasic cerebellar gangliocytoma. A slow-growing benign cerebellar tumour. On T2 MRI is has characteristic 'tigroid' stripes.
Marburg variant of multiple sclerosis (MS) - an aggressive form of MS, usually with multiple large and even tumefactive (i.e. having mass effect) lesions. Patients can die from brain herniation and sometimes need neurosurgical decompression to save their lives.
Marchiafava-Bignami disease - a demyelinating disease seen with chronic alcoholism, featuring corpus callosum necrosis. On imaging this may be partial, affecting the central fibres and sparing the outer ones - known as the sandwich sign. Clincial features include cognitive impairment and there may be disconnection syndromes due to impaired signalling between hemispheres.
Meniere's disease - a chronic inner ear disorder featuring recurrent attacks of vertigo, tinnitus, hearing loss (for lower frequencies), and a sense of fullness in the ear - lasting under 24 hours. From a localisation perspective, the nystagmus during attacks is irritative - the eyes are pushed away from the affected side, then beat back to it (similar to the effects of warm water irrigation). However, this reverses after the peak of attacks as the affected side becomes hypoactive, so the eyes now drift toward it then beat away (similar to cold water irrigation).
Melkersson-Rosenthal syndrome - a chronic, episodic disorder featuring recurrent bouts of lower motor neuron facial palsy, lip swelling and a fissured tongue. It’s rare, but worth thinking about if you ever see recurrent facial palsy - though there are other causes of this such as sarcoidosis.
Miller-Fisher syndrome - a variant of Guillain-Barré syndrome associated with to anti-GQ1b antibodies. The features are opthalmoplegia, ataxia and areflexia. It sometimes mimics brainstem strokes, Wernicke’s and myasthenia gravis. The evolution, lack of cognitive features and the absence of ptosis go against each.
Mollaret's meningitis – recurrent aseptic meningitis, linked to Herpes Simplex 2 virus. Atypical cells - known as Mollaret cells - can be seen.
Ondine's curse - loss of respiratory drive during sleep (i.e. central hypoventilation). Can be due to various insults to the brainstem.
Pancoast tumour - an apical lung mass invading the lower trunk of the brachial plexus, causing features such as hand wasting and Horner's syndrome, often with pain.
Parry-Romberg syndrome - a sporadic disorder with hemifacial atrophy. There is sometimes an area of morphoea over the forehead - ‘linear coup en sabre’ - and underneath this there is often a brain abnormality that can lead to focal seizures.
Parsonage-Turner syndrome - i.e. brachial neuritis. A painful episode of inflammation in the brachial plexus, beginning with shoulder pain then followed by weakness and sensory disturbance. Sometimes this is triggered, for example by infections (hepatitis E), surgery or childbirth. A genetic form exists - arising with variants in the SEPT9 gene.
Pick’s disease - a subtype of frontotemporal lobar degeneration (FTLD) which causes behavioural variant frontotemporal dementia, associated with accumulation of tau in the brain. Features include disinhibition, loss of empathy and sympathy and hyperorality.
Pott's spine - tuberculosis of the spine causes vertebral deformity. This may lead to neurological compromise. They may also have infectious discitis.
Ramsay-Hunt syndrome - there are two of these. The second is vastly better-known - almost every doctor knows of it, whereas many don't know the second - including many neurologists:
Rassmussen's encephalitis - an inflammatory disease of children and teenagers featuring progressive damage and atrophy of one hemisphere, characterised by continuous focal seizures (epilepsia partialis continua), and treated by unilateral hemispherectomy.
Rowland-Payne syndrome – a combination of Horner's, unilateral vocal cord palsy and hemidiaphragmatic weakness due to a lesion affecting the sympathetic chain, recurrent laryngeal nerve and phrenic nerve in the apical lung.
Strachan syndrome - a vitamin deficiency syndrome seen with malnutrition. The major effects are on the sensory nerves (sensory axonal polyneuropathy), optic nerve and cochlear nerve. Originally described in people in the Caribbean.
Sturge-Weber syndrome - a disorder present from birth, with a ‘port wine stain’ over part of the face and abnormal vessels overlying the brain. The main issue is seizures. It's due to a somatic mutation in a gene.
Susac syndrome - an autoimmune disease with vasculitis affecting retinal arteries as well as those to the cochlea and cochlear nerve, causing visual and hearing loss. It also affects the CNS, with characteristic 'snowball' lesions in the corpus callosum.
Sydenham's chorea - a post-infectious complication of rheumatic fever, with chorea developing as a result of molecular mimicry. Antibodies are made which react to the basal ganglia, leading to chorea. Another name for this was St. Vitus' dance - after the patron saint of dancers - although Sydenham's description later supplanted this term and the eponym is still used. It's become a lot rarer now thanks to antibiotics.
Tapia syndrome – combination of X and XII palsy, oriignally described in a bullfighter who was gored through the neck, though nowadays mainly seen as a complication of endotracheal intubation.
Tolosa-Hunt syndrome - idiopathic granulomatous inflammation in the orbit and cavernous sinus regions. Causes pain and ophthalmoplegia. Very steroid-responsive. The key is making sure this is not anything else prior to committing to a steroid course - for example, lymphoma or infections (TB, fungal). Similar appearances may arise in more widespread, multisystem inflammatory diseases such as sarcoidosis, IgG4-related disease and granulomatous vasculitis.
Todd's paresis - unilateral weakness following a seizure, which resolves within 24 hours. It can mimic a stroke, particularly if the seizure was unwitnessed and the patient is found drowsy with hemiparesis.
Tumarkin crisis - a sudden collapse as if pushed to the ground, seen in Meniere's disease.
Useless hand of Oppenheim - proprioceptive loss (deafferentation) causing sensory ataxia in an arm, with functional consequences ('uselessness') - often with pseudoathetosis (involuntary movements when the patient is not looking or has eyes shut). Usually due to dorsal column disease - Oppenheim's original description was in multiple sclerosis. Key clues are loss of vibration and proprioceptive sensation (which we often omit on sensory testing upper limbs) and lack of true weakness even though the patient may feel their hand is weak. They have better strength with eyes on the hand than with eyes shut.
Vernet syndrome – palsies of nerves IX-XI as they pass through the jugular foramen - i.e. jugular foramen syndrome. Many causes exist but thrombosis of the jugular vein and tumours (e.g. paraganglioma) are important ones.
Villaret syndrome – palsies of nerves IX-XII plus Horner's. Usually pathology in the carotid sheath, although there are other causes such as tumours or infections.
Von Hippel-Lindau disease – a genetic disorder caused by pathological variations in the VHL tumour suppressor gene. The main tumours that grow are haemangioblastomas in the retina, cerebellum and spine, but also increased risk of renal cell carcinoma.
Wallenberg's syndrome - a lateral rostral medullary lesion, usually infarct (in the PICA territory), takes out several structures - nuclei and tracts - in one move. Often the cerebellum is also affected. Vertebral artery dissection is an important cause. Features include:
Wartenberg's migrant sensory neuritis – recurrent sensory mononeuropathies in different nerves. A benign but unpleasant condition.
Wartenberg's syndrome – pain and numbness in the dorsal hand, due to compression of the superficial sensory nerve between brachioradialis and extensor carpi radialis longus muscles in the forearm. Also known as cheiralgia paraesthetica. As the name suggest this nerve is purely sensory - it parted ways with the posterior interosseous nerve (the major motor nerve) higher up.
Wernekink commissure syndrome - a caudal paramedian midbrain lesion affects both superior cerebellar peduncles as they decussate on their way to the red nucleus, as well as the medial longitudinal fasciculi, so features include ataxia and ophthalmoplegia.
Wernicke’s aphasia – lesion in the superior temporal gyrus. Fluent but incomprehensible speech, with the patient unaware of the issue (they can't monitor their own speech), and completely unable to understand others.
Wernicke’s encephalopathy - an acute disorder due to thiamine deficiency - whether through poor diet (including alcoholism) or gut issues. This deficiency is chronic, but something tends to trigger Wernicke’s - usually an illness increasing metabolic demand such as fever or vomiting (including hyperemesis in pregnancy). Features are confusion, particularly amnesia, with ophthalmoplegia and ataxia. If not recognised and treated, irreversible brain damage occurs - so have a very low threshold to give intravenous B-vitamins in anyone who may have this. The typical scan features can be seen here.
Less relevant to localisation
Far more eponyms exist for diseases that don't localise as neatly, often being multi-system or describing phenomena that aren't due to a (known) focal process.
Aicardi syndrome - a disorder affecting young girls with problems including epilepsy and cognitive impairment. The corpus callosum is absent, among other malformations.
Aicardi-Goutiere's syndrome - an auto-inflammatory disease due to problems with interferon excess, leading to damage to multiple tissues. There is widespread neurological decline (including intellectual impairment, dystonia and epilepsy), as well as systemic features such as fever and cutaneous chilblain lesions.
Batten disease - a group of conditions associated with the build up of lipofuscin in the nervous system and eyes (neuronal ceroid lipofuscinosis).
Bing-Neel syndrome - an infiltrative consequence of Waldenström's macroglobulinemia, a form of lymphoma. Clonal cells invade brain, spinal cord and nerves.
Binswanger's disease - subcortical dementia due to small vessel disease. Particular problems include poor attention and executive dysfunction rather than the amnesia which is typical of Alzheimer's. The classic description was of a stepwise decline due to repeated infarcts, rather than progressive and linear, in contrast to neurodegenerative illnesses - but in reality progression is often continuous. The term isn't commonly used now, but 'vascular dementia' as an umbrella term includes lots of forms, including this.
Charcot-Marie-Tooth disease – a large family of hereditary neuropathies. Type 1 and 2 are autosomal dominant, and feature demyelination or axonal damage respectively. The spectrum of specific subtypes (CMT1A, 1B, 1X etc) is vast and not worth memorising.
Churg-Strauss disease - a form of small vessel vasculitis associated with eosinophils. Involves multiple organs such as the lungs (including late-onset asthma), nasal sinuses (polyps), kidneys (glomerulonephritis), and from the neurological perspective the major manifestation is mononeuritis multiplex, generally evolving rapidly over days-weeks. Extremely dangerous but treatable. The eponym is discouraged (Nazi affiliations) but often still used, unfortunately.
Doose syndrome – a form of childhood epilepsy featuring myoclonus and atonic drop attacks - hence, myoclonic-atonic epilepsy
Dravet syndrome - an acquired (sporadic/de novo) mutation in a sodium channel causes a severe, drug-refractory epilepsy manifesting in infants. Seizures are often induced by temperature spikes. As well as epilepsy there are progressive neurological problems and developmental delay. Some treatments now exist that help it, including cannabis-based.
Fahr disease and Fahr syndrome - calcification of the basal ganglia and other brain regions. 'Disease' refers to a familial pattern (various genes exist e.g. SLC20A2), while non-genetic causes are best-known in endocrine disorders e.g. hypoparathyroidism. Features include parkinsonism, chorea, and cognitive decline.
Gordon-Holmes syndrome - a genetic condition featuring hypogonadism and ataxia. Cognitive impairment also develops.
Kleine-Levin syndrome - a rare condition affecting teenage boys, causing recurrent episodes of hypersomnia (often about 20 hours a day), typically lasting a week, with return to completely normal sleep patterns in between these. Often there is infantile behavioural regression during these episodes, with hypersexuality and hyperphagia, though in some cases the issue is just sleepiness. The cumulative effect of these episodes is significant, with missed time in school leading to failing exams and participation in hobbies (e.g. sports teams).
Krabbe disease – a genetic disorder affecting white matter due to build-up of sphingolipids.
Kufor-Rakeb syndrome - a genetic cause of childhood/adolescence-onset parkinsonism with spasticity, supranuclear gaze palsy, and myoclonus (of face, palate and fingers). The parkinsonism responds to levodopa.
Kufs disease - adult-onset neuronal ceroid lipofuscinosis (i.e. adult-onset Batten disease). Features may include cognitive decline, progressive myoclonic epilepsy and ataxia. Unlike the childhood form, vision is spared. Multiple genes are associated.
Labrune syndrome – a rare genetic disorder featuring white matter disease with calcifications and cysts. Causes progressive cognitive decline with seizures and motor problems.
Lance-Adams syndrome – hypoxic brain injury leads to myoclonus, often pronounced in the lower limbs on walking - leading to a ‘bouncy gait’
Landau-Kleffner syndrome – after normal development of language, a child experiences progressive loss of language capacity (understood and spoken/written). There are abnormal EEG changes seen during slow-wave sleep.
Lafora body disease - a form of progressive myoclonic epilepsy with recessive inheritance, causing progressive, incurable, neurodegeneration associated with aggregates of polyglucosan, which can be shown no biopsy.
Leigh disease - a mitochondrial disorder (various mutations exist) affecting children. The presentation is often subacute and features basal ganglia necrosis, as well as affecting other areas in the brain and spine, causing movement disorders, hypotonia, spasticity, ataxia, seizures and broad neurological decline.
Lennox-Gastaut syndrome - a progressive epileptic encephalopathy in children with multiple causes. Seizure types seen include absence, atonic (drop attacks), and generalised tonic-clonic types. The EEG shows slow spike-and-wave changes.
Lubag syndrome - an X-linked disorder featuring dystonia and parkinsonism, usually beginning in teens. Mostly seen in men from the Philippines.
McArdle's syndrome - an autosomal recessive genetic disorder and a form of glycogen storage disease. There is failure of glycogen breakdown into glucose for anaerobic respiration. The result is pain and cramping during intense exercise, arising early on (in contrast to disorders of fatty acid oxidation). The issue is in the muscles however, and glycogen can be broken down elsewhere, and then reach the muscles through the blood - so there is often a 'second-wind' phenomenon, with improved muscle function after a few minutes.
McLeod syndrome - an X-linked disorder affecting multiple tissues, including blood (causing acanthocytosis), the brain (chorea, psychosis and cognitive decline), nerves, muscles and heart muscles. It can mimic Huntington's, but has a much broader range of effects, some of which are life-threatening (cardiac) in their own right.
Meige syndrome - a combination of dystonias affecting the head: blepharospasm and oromandibular dystonia. The disorder is idiopathic. Mostly seen in women age 50-70. Botox injections can help.
Mohr-Tranebjærg syndrome - otherwise known as 'dystonia-deafness syndrome'. An X-linked condition causing hearing loss in early childhood (having started with intact hearing), then dystonia in teens, often with visual deterioration in adulthood.
Olser-Weber-Rendu syndrome – a genetic disorder featuring arteriovenous malformations (AVMs) in multiple organs, particularly brain, spine, lungs, liver and gut. There are also cutaneous lesions easily visible over the lips. The major neurological manifestations are haemorrhage, epilepsy and sometimes the consequences of mass effect (e.g. myelopathy).
Panayiotopoulos syndrome - a childhood epilepsy with autonomic activity including pupillary changes, flushing, salivation and vomiting. The modern name is self-limited epilepsy with autonomic seizures (SeLEAS). This is one of the best examples of the problems with eponyms - they tell us nothing, whereas the words that spell SeLEAS describe this perfectly, including the good overall prognosis, with remission eventually developing.
Pelizaeus-Merzbacher disease - an X-linked disorder with multiple effects, presenting in childhood. Neurology-wise, these include hypotonia, nystagmus, ataxia and sometimes cognitive impairment. There is characteristic 'rolling' head movements (titubation).
Pompe's disease - a genetic disorder affecting glycogen processing, leading to excessive storage in lysosomes and progressive muscle failure. This may manifest in childhood but also in adults, causing progressive myopathy affecting movement and breathing (with type-II respiratory failure). Treatment exists in the form of enzyme replacement infusions.
Refsum's disease - an autosomal recessive disease featuring build-up of phytanic acid, damaging tissues: retina, nerves, cerebellum, olfactory nerve, and also the skin and bones. Treatable with dietary adjustments, if diagnosed!
Rett syndrome - an X-linked condition, but mainly affecting girls, and spontaneously arising de novo rather than being hereditary. Features including developmental delay after initially normal development before age 2, autism, loss of previous language and motor skills, and stereotypic repetitive hand movements (often wringing). Seizures may be seen too.
Sandifer syndrome - head and body movements seen in children with acid reflux. It can mimic other conditions like seizures - but is actually a reactive response to the unpleasant sensation of reflux. A clue is that it appears after feeding.
Segawa syndrome - dopa-responsive dystonia. There are dominant and recessive forms, all affecting metabolism of dopamine from precursors. Patients develop dystonia mainly in the legs and trunk which responds well to low-dose levodopa. Unlike Parkinson's, this is not neurodegenerative - so patients don't tend to need increasing doses, nor do they get dyskinesias. This is a condition 'not to miss' - as it's easily treated!
Steinert disease - myotonic dystrophy type 1. A relatively common genetic disorder affecting chloride channels in muscles, causing progressive myopathy (including facial), cardiac conduction problems, diabetes, fertility issues, cataracts, balding, and characteristic myotonia induced by muscle contraction, for example handshakes.
Tarui disease - a glycogen storage disease due to enzyme failure of glycogen breakdown in the muscles, causing pain and cramps on exercise. This is similar to the commoner McArdle's disease. One difference is Tarui's features an 'out-of-wind' phenomenon with glucose intake leading to worsening pain and fatigue, due to this preventing fatty acid usage. Another is that the 'second wind' phenomenon is not seen.
Thomsen disease - myotonia congenita. A muscle disease due to a dysfunctional channel. Features include muscle cramps and inability to relax after contraction, e.g. eyes remaining closed on sneezing. People affected have unusually large muscles despite not necessarily partaking in exercise of the type that would explain this. The disorder is not progressive, unlike the dystrophic myotonias, but can cause life-threatening complications if not known about, for example during anaesthesia.
Tourette's syndrome - a developmental condition beginning in childhood or teens, but not in adulthood (even though adults may seek attention for longstanding issues). People affected experience tics, both motor and vocal, which are very varied between individuals. The tics feature an urge, which can be delayed but not forever (a bit like sneezing) - people often suppress them until they have some privacy then release a flurry of tics. Tics can be further classified into simple versus complex motor or vocal forms. Despite cultural stereotypes, swearing (coprolalia) is not common, and in those who do display this, the tic is often a truncated swear word (e.g. 'f-' or 'shi-'). ADHD and OCD are quite common co-morbidities.
Unverricht-Lundborg disease - the commonest form of progressive myoclonic epilepsy (PME), caused by having two pathological variants in CSTB. Presents in childhood or teens, with progressive myoclonus, often action- or stimulus-induced, as well as epilepsy and ataxia. An old name was Baltic myoclonus
Waisman syndrome - a rare, X-linked disorder featuring intellectual impairment followed by early-onset parkinsonism.
Wegener's granulomatosis - also known as granulomatosis with polyangiitis (GPA). A form of small vessel vasculitis featuring granulomatous inflammation. Characteristically affects the orbit, sinuses and upper airways, as well as the lungs, kidneys and skin. The major neurological manifestations include cranial nerve palsies (direct inflammation and also orbital granuloma compressing them) and mononeuritis multiplex. It can also cause meningeal disease. Direct brain parenchymal involvement is rare. The eponym is discouraged (Nazi affiliations) but some still use it.
Werdig-Hoffman disease - an old name for spinal muscular atrophy (SMA) type 1, a genetic disorder of lower motor neurons affecting infants. This is the most severe type, and affected people never learn to sit, crawl or walk and may have issues with breastfeeding. This was one of the first neurological disorders in which gene therapy was developed using anti-sense oligonucleotide technology, inspiring a wave of efforts to develop similar treatments for other diseases.
West syndrome - a pattern of epilepsy and developmental delay in children. There is not just one cause for this - for example genetic mutations and tuberous sclerosis can be causes. Seizures include characteristic 'salaam attacks', bringing the head to the floor. The EEG shows a chaotic, disorganised pattern termed hypsarrhythmia.
Weston-Hunt syndorme - a rare and deadly form of acute disseminated encephalopmyelitis (ADEM), an immune disease often following infection. In Weston-Hurt there are haemorrhagic white matter lesions which are usually very swollen.
Non-eponymous syndromes
Agrypnia excitata - a dramatic syndrome with hyperactivity, agitation, delirium, altered sleep-wake cycles, and autonomic hyperactivation (e.g. sweating and tachycardia). A major cause is alcohol withdrawal (delirium tremens) - but rarer ones include Morvan syndrome (an anti-potassium channel antibody disease) and fatal familial insomnia (a genetic prion disease).
Anterior lobe syndrome - The cerebellar vermis and paravermis are sometimes called the anterior lobe. Damage causes truncal and gait ataxia but little in terms of signs in individual limbs (e.g. dysmetria), unlike lesions in one of the cerebellar hemispheres (posterior lobe).
Area postrema syndrome - an area in the caudal medulla is sensitive to blood chemistry and is involved in the vomiting reflex. Damage here can lead to problems such as hiccups, nausea and vomiting, and it is particularly associated with neuromyelitis optica - and is a typical feature, hence is included in the diagnostic criteria for the disease.
Burning mouth syndrome - a persistent feeling of burning in the oral cavity. Often idiopathic rather than having an identifiable cause. Seen in older women.
Caudal paramedian midbrain syndrome – the same as Wernekink commissure syndrome, defined above in the eponymous section.
Cruciate paralysis – an unusual pattern of bilateral arm weakness (brachial diplegia) with intact leg strength, due to a central lesion causing damage at the decussation point of the bilateral corticospinal tracts supplying the arms, above the point where the tracts to the legs decussate.
Cortical blindness - visual loss in all quadrants (i.e. bilateral heminaopia!) due to bilateral cortical disease. Anosoagnosia for the deficit (Anton-Babinski syndrome) is typical, so this is often found on examination, rather than being reported in history - many people don't complain of blindness or realise they can't see. If you look, though, it becomes evident during the history that they aren't quite looking at you.
Facial colliculus syndrome – a lesion at the dorsal caudal pons, affecting the facial colliculus - a mound where the fascicle of VII runs round the nucleus of VI. The effect is inability to look to the affected side (conjugate gaze - both eyes) and lower motor neuron-pattern facial weakness.
Foreign accent syndrome - a sudden change in the patient’s speech pattern, taking on a foreign accent. It’s often of a place the patient has never been or had any particular contact with. The patient is aware of it and finds it bizarre. While this is thought to be functional, it is also associated with structural brain lesions, particularly from stroke.
Harlequin syndrome – unilateral sympathetic chain damage leads to ipsilateral anhidrosis over the chest, neck and face. During exercise or emotional situations the patient flushes, but only on the intact side - leading to a unique appearance.
Malignant middle cerebral artery syndrome - a major ischaemic stroke in the middle cerebral artery (MCA) territory leads to swelling with mass effect - i.e. space-occupying infarction. The skull is a closed box, so the only way for brain tissue to move is away from it - hence there is brain herniation which is usually fatal. Decompressive craniectomy (i.e. removal of a large piece of skull) saves lives, but survivors are usually left very disabled. Malignant MCA syndrome is mainly seen in the young - older patients’ brains have a degree of atrophy that usually gives space to accommodate such swelling. It manifests with worsening neurological status and falling consciousness 2-3 days into a stroke, so is one of several causes of neurological deterioration (others include seizure, haemorrhage, and intercurrent medical issues such as infection).
Meralgia paraesthetica – numbness and tingling in the antero-lateral thigh, due to entrapment of the lateral cutaneous nerve under the inguinal ligament. Often seen in overweight people.
Moyamoya disease - bilateral narrowing of the intracranial parts of the internal carotid arteries, leading to stroke/TIA. Mostly a paediatric disorder. The angiographic appearances resemble a 'puff of smoke' - the name is Japanese for this.
Myelomeningocoele - a neural tube defect. Normally the tube closes early in gestation. Here it stays open, and at birth there is a sac bulging outward, containing parts of spinal cord and cauda equina. Issues if untreated include flaccid weakness, hypoplasia (not really atrophy - the legs don't develop in the first place rather than growing normally then losing muscle), problems with bladder, bowel and sexual functions, and orthopaedic complications, particularly in the feet.
Neck-tongue syndrome - neck rotation triggers ipsilateral tongue pain and sometimes abnormal posturing. The hypoglossal nerve is anastomotically linked to the upper cervical nerves in the neck and the trigeminal (sensory) nerve in the tongue, hence the sequence. Essentially this is referred neck pain manifesting in the tongue.
Notalgia paraesthetica – paraesthesia including itch and burning in the area below the shoulder blade. There may be skin changes as a result of scratching the skin.
Numb chin syndrome - numbness over one side of the chin, reflecting a problem in the mental nerve, a branch of V3. This might sound trivial, but it's not - it's associated with a range of metastatic cancers, particularly breast. Take the numb chin very seriously.
Occipital condyle syndrome – pain on head turning, associated with an XII palsy. Cancer is a major cause as well as tuberculosis.
Orbital apex syndrome - simultaneous damage to III-IV-VI, II and V1, causing ophthalmoplegia, monocular visual loss and forehead numbness. It resembles cavernous sinus syndrome but also includes II, and doesn't include V2. Causes include infections (particularly fungal), tumours and inflammatory lesions such as grabuloma (e.g. Tolosa-Hunt syndrome).
Oromandibular dystonia - dystonia involving the jaw but also often the perioral muscles and the tongue. This leads to abnormal postures or facial expressions and sometimes hazardous spasms leading to damaged teeth, lips and tongue. Patients sometimes find chewing a toothpick helps relieve this - a form of sensory trick.
Parakinesia brachialis oscitans – - paralysis of the arm for voluntary actions, but intact arm movement on yawning. This is a true example of the separation between automatic and voluntary movements. Be careful not to mistake this for a functional problem - there is genuine paralysis of the pyramidal system.
Peduncular hallucinosis – visual hallucinations due to upper brainstem damage. They are often very vivid and while people know they are imaginary, they are unpleasant. The mechanism may be a form of intrusion of REM activity into waking life - a release phenomenon.
Person in a barrel syndrome – weakness of both arms with retained leg strength. The classic cause is bilateral borderzone ('watershed') infarctions affecting the intersection zone between anterior and middle cerebral artery territories, making the shoulder-innervating areas of the motor homunculus weak. There are other causes however, for example bi-brachial amyotrophy, variants of Guillain-Barré syndrome, and cruciate paralysis due to damage at the pyramidal decussation. Another cause not to miss is not actually weakness but bilateral shoulder dislocation - sometimes seen after seizures.
Pituitary apoplexy – a tumour in the pituitary outgrows its own blood supply and infarcts or bleeds into itself. The manifestations include thunderclap headache, bitemporal heminaopia and pituitary failure (including shock from adrenal insufficiency).
Posterior reversible encephalopathy syndrome(PRES) - vasogenic oedema affecting bilateral occipital lobes and often some of the parietal and temporal lobes. Often associated with severe hypertension. Triggers include drugs (particularly for transplants or chemotherapy) or hypertensive crises, including eclampsia. The manifestations are confusion/coma, visual disturbance (including cortical blindness and Anton-Babinski syndrome) and seizures.
Pusher syndrome - a pattern of abnormal walking seen in people with hemiparesis and often hemispatial neglect. They push with the intact side and end up tilted and can fall. Particularly seen in the rehab setting.
Reversible cerebral vasoconstriction syndrome (RCVS) - also known as Call-Fleming syndrome, and in the context of maternal neurology benign post-partum angiopathy. This is diffuse spasm of intracranial arteries leading to recurrent thunderclap headaches. Sometimes there are one or more areas of small, convexity subarachnoid haemorrhage. Delayed ischaemia, often in a borderzone (‘watershed’) distribution, can be seen, usually at least a week after onset. RCVS is sometimes triggered by medication or drug abuse. It resolves over weeks, but it can be dangerous. The major diagnostic challenge is distinguishing from other disorders, particularly various forms of vasculitis.
Split-brain syndrome - corpus callosum damage leads to complex clinical features all due to inability of the hemispheres to send signals between each other. In general, when one hand, usually the left, is used, the person cannot also do something relating to this that the same hemisphere is involved in - for example naming objects it's holding(tactile anomia) or copying gestures (apraxis). The left hand is mapped to the right hemisphere, but other left hemispheric functions cannot be performed in relation to the left hand. The right hand has no such issue as it directly maps to the left hemisphere.
Stiff person syndrome - excessive muscle activity leads to a combination of problems including an abnormal stiff posture with hyperlordosis in the spine, difficulties with movements, and a tendency to sudden spasms triggered by noise or surprise - which may lead to falls. As a result patients become phobic of tasks such as crossing roads. Variants exist, for example stiff limb syndrome or stiff face syndrome. It's caused by antibodies to enzymes or receptors involved in neuronal inhibition, or example glutamic acid decarboxylase (GAD) or glycine. Some cases are paraneoplastic, particularly linked to breast cancer.
Subacute sclerosing pancencephalitis (SSPE) - reactivation of measles within the CNS, several years after primary infection - causing a rapidly progressive, fatal, brain disease with characteristic 'hung-up' myoclonus, dementia and mobility problems. EEG has characteristic changes (Radenecker complexes), and MRI shows white matter abnormalities. This shouldn't exist in the modern era, at least not in countries with high healthcare resource levels - but changing attitudes around vaccination have led to reduced uptake, falling rates of 'herd immunity', and resurgence of measles - inevitably, SSPE cases will follow, and already are being seen.
Sunken flap syndrome - hemicraniectomy, e.g. for malignant MCA syndrome, leads to a defect that is sealed by dura but not skull, until later correction. It can be followed by progressive changes in cognitive function. The cause may be atmospheric pressure pushing down on the brain.
Syndrome of the trephined - See sunken flap syndrome
Thoracic outlet syndrome - compression of structures in the neck and shoulder leading to either vascular or neurogenic compromise, triggered by arm movements.
Trigeminal trophic syndrome - facial numbness leads to habitual scratching and picking at skin. Patients end up with many scars and ulcers on the numb side of the face.
Wall-eyed bilateral internuclear ophthalmoplegia (WEBINO) - bilateral INO due to damage to the midline pontine tegmentum, affecting bilateral medial longitudinal fasciculus (MLF) fibres, which both and ascend either side of the midline after decussating in the inferior pons (forming an X). One eye also becomes exotropic (turned out), hence ‘wall-eyed’ (similar to the position the eye takes in paralytic pontine exotropia, a similar disorder but featuring one-and-a-half syndrome rather than bilateral INO). The term 'wall-eyed' isn't exactly kind or aligned to modern language, but the acronym does remain used, which is a shame. Perhaps 'bilateral INO with exotropia' would be kinder.
Pathological terms
Non-eponymous pathological terms
Abscess - a walled-off area containing infective and inflammatory material. The major causes are bacterial and fungal.
Axonotmesis - the intermediate/moderate grade of a compressive nerve injury. The axon is damaged though the entire nerve is not - unlike in neurotmesis, the most severe form.
Cerebritis - bacteria in the brain parenchyma don't cause encephalitis (usually, though some can) - but form an abscess, with a wall surrounding it. Before this, the infection and inflammation in a small area is termed cerebritis. An important cause is spread via an ear infection - leading to otogenic brain abscess.
Coiled body - oligodendrocyte includes of tau, seen in conditions such as corticobasal degeneration.
Cortical laminar necrosis - death of cortical cells due to metabolic insults, particularly ischaemia or prolonged epileptic seizures. It's visible on T1 MRI sequences as bright lines of cortex, often emerging after a delay from the initial insult.
Cyst - a round structure containing fluid. Many types exist, such as arachnoid cysts, colloid cysts, tumours such as cystic glioblastoma, and infections - most prominently neurocysticercosis (a helminth infection which is a major cause of epilepsy worldwide).
Demyelination - damage to the myelin sheath around nerves, whether in the central nervous system (the oligodendrocytes) or peripheral (Schwann cells). This is often due to inflammation though there are other causes such as vitamin deficiencies, toxic exposures, and genetic disorders such as Charcot-Marie-Tooth disease.
Denervation - loss of nerve supply to a muscle, leading to characteristic features. Clinically these include atrophy and fasciculations. On imaging the muscles may show oedema as a reactive change, then progressive atrophy and fatty infiltration.
Encephalomalacia - softening of the brain matter as a consequence of damage
Fistula - abnormal connection between two structures. In neurology the main examples are arteriovenous fistula (causing ischaemia and infarcts) and CSF-venous fistula (causing intracranial hypotension)
Focal cortical dysplasia - a region of disorganised cortical structure, associated with drug-refractory epilepsy
Gliosis - astrocyte increase in number and activity at an injury site in the central nervous system, leading to scarring.
Globose tangle- round aggregates of pathological hyperphosphorylated tau within neurons, particularly seen in progressive supranuclear palsy, a neurodegenerative disorder with features somewhat resembling Parkinson's disease but a diferent course.
Inclusion body - a substance, usually a misfolded protein aggregate, within a cell.
Infarction - death of cells following the effects of ischaemia - which compromises their ability to manage ion pumps and prevent cytotoxic oedema. Ischaemia may be reversible - as happens spontaneously in a TIA, or with reperfusion therapy for stroke - but infarction is permanent.
Liquefactive necrosis - cell death with cells being dissolved into a liquid mass, often with pus. Causes include infarction and infection.
Mesial temporal sclerosis - a condition associated with focal seizures which are often refractory to medications.
Myelinolysis - another word for demyelination, but only really used in relation to osmotic damage, especially from low sodium which is corrected too quickly, leading to swollen myelin sheaths breaking. This can be devastating - in the pons, it can cause locked-in syndrome.
Myelitis – inflammation of the spinal cord (inflammatory myelopathy)
Myelopathy -spinal cord disease, of any kind - though 'myelopathy' is often used to mean ‘compressive cervical myelopathy’, usually due to discs or other degenerative pathologies.
Myeloneuropathy -combination of cord and peripheral nerve disease (e.g. B12 deficiency)
Myositis- inflammation of muscle fibres. Many causes exist including immune diseases and drugs
Neurapraxia - inflammation in one or more nerves. The term isn't used that much anymore.
Neuritis - compressive damage to a nerve, altering its transmission - but only temporarily. You've almost certainly had this when you slept on an arm and awoke with it feeling 'dead'
Neurofibrillary tangle - hyperphosphorylated tau accumulation within neurons, particularly seen in Alzheimer's disease
Radiculitis – inflammation at a root (e.g. from infection such as Lyme disease)
Radiculopathy - compression of a root, by any cause (though often used to imply a disc prolapse)
Rhabdomyolysis - fulminant and overwhelming breakdown of muscle fibres, leading to consequences such as myoglobin accumulation and obstruction within renal tubules, and electrolyte derangement
Siderosis - iron deposition, usually around the brain and spine though sometimes within their parenchyma. It's a consequence of chronic bleeding - usually the slow, oozing type. It can irritate the brain, causing various disturbances such as spreading depression or seizure, and can also affect cortex and cranial nerves, particularly VIII (causing deafness).
Spondylolisthesis - anterior slippage of one vertebral body on top of another
Spondylosis - age-related degeneration of the vertebral column (including disc prolapse, osteophytes, facet joint hypertrophy)
Spongiform change - vacuoles present in an area of degenerating tissue, best known in prion diseases.
Tumefactive - a lesion (or multiple) that is not a tumour but has a space-occupying effect (mass effect on adjacent structures, surrounding oedema) and resembles a tumour - typically with round, sizeable lesions that often have contrast enhancement on imaging. This term is particularly used in inflammatory lesions. Tumefactive multiple sclerosis is an example.
Vasculitis - inflammation of blood vessels, usually arteries but sometimes also veins (venulitis). Can be autoimmune, infectious (particularly with syphilis and Varicella-Zoster) or drug-induced. Classified further according to vessel sizes involved (small, medium or large) and whether it is systemic or purely arising within the central nervous system
Eponymous pathological terms
Charcot-Bouchard aneurysm - a debated entity. They are thought to be tiny micro-aneurysms in the deep perforator vessels in the brain, associated with chronic hypertension, and able to rupture causing intracerebral haemorrhage. However the main cause is probably microvascular disease (‘small vessel disease’) of a non-aneurysmal type.
Lewy body - alpha synuclein aggregates in neuronal cell bodies, associated with Parkinson's disease and dementia with Lewy bodies.
Papp-Lantos body - oligodendrocyte cytoplasm inclusions of alpha-synuclein, seen in multiple systems atrophy (MSA)
Pick body - inclusions of tau (3R type) in the cytoplasm of neurons in the frontal and temporal lobes, associated with degeneration in these. they are seen in Pick's disease, a tauopathy.
Virchow-Robin space - perivascular spaces; the pia mater surrounds vessels penetrating the brain parencyhma, and vessel disease leads to these spaces enlarging and becoming prominent. They are harmless but can be mistaken for lesions such as lacunar infarcts. Occasionally they are giant and tumefactive and in that form they may cause symptoms - though often look dramatic imaging yet have no clinical effects.
Wallerian degenration - the 'dying back' of an axon, due to severe damage separating it from the cell body. This is part of many neurodegenerative disorders, and is best known in motor neuron disease.
Radiological abnormalities
(Under construction...)Historical figures with eponyms (for interest)
(Under construction...)Bannwarth, Alfred (1903-1970) - German neurologist. In 1941 he characterised a syndrome (facial palsy, radicular pain, lymphocytic CSF) we now recognise as due to Lyme disease, though at the time this wasn't known. It wasn't until the 1980s that the cause was recognised as Lyme
Charcot, Jean-Martin (1825-1893) - French neurologist who worked at the Salpetriere in Paris and is arguably the father of much of modern neurology. His impact is gigantic. Eponymous legacies include two triads (MS, cholangitis), Charcot's spine (TB), Charcot joints (neuropathic foot damage), Charcot-Marie-Tooth disease, disputed Charcot-Bouchard microaneurysms, and to the French, La Maladie de Charcot (MND).
Godtfredtsen, Erik (1913-1993) - Danish ophthalmologist who studied ophthalmogical complications of nasopharyngeal cancers. One pattern - combined VI and XII palsy - was his own original discovery and bears his name, and reflects involvement of the clivus. The XII palsy was postulated as due to metastasis to draining retropharyngeal nodes near the extracranial path of XII. It may also be due to hypoglossal canal involvement.
Marie, Pierre (1853-1940) - French neurologist who trained under Charcot. Researched acromegaly and pituitary diseases, but also aphasia and stroke. Eponymous legacies include Charcot-Marie-Tooth disease, Marie-Foix and Foix-Marie-Chauvagny.
Mollaret, Piere (1898-1987) - French physician. Trained under Guillain. Main discoveries include Mollaret's meningitis (recurrent lymphocytic meningitis, later identified as due to HSV2), and the Guillain-Mollaret triangle (dentate - red nucleus - olive), important in particular movement disorders.
Parkinson, James (1755-1824) - English surgeon who wrote the classic 1817 ‘Essay on the shaking palsy’. He called it ‘Paralysis agitans’ - Charcot later studied and described it and named it after Parkinson.
Tooth, Howard Henry (1856-1925) - London-based English neurologist. Eponymous legacies include Charcot-Marie-Tooth disease, which he characterised separately to the other two French neurologists it's named after.
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