thus CSF is produced at a rate of approximately 700 mL per day.
The spinal cord contains afferent and efferent fibres arranged
in discrete bundles (pathways running to and from the brain),
which are responsible for the transmission of motor and sensory
information. Peripheral nerves have myelinated and unmyelinated
axons. The sensory cell bodies of peripheral nerves are situated in
the dorsal root ganglia. The motor cell bodies are in the anterior
horns of the spinal cord (Fig. 7.1).
7.1 Clinical characteristics of headache syndromes
Onset Duration/periodicity Pain location Associated features
Aura (usually visual), nausea/vomiting,
Cluster headache Rapid onset, often
conjunctival injection, tearing, nasal
stuffiness, ptosis, miosis, agitation
Meningitis Usually evolves over a
Fever, meningism, rash, false localising
signs, signs of raised intracranial
20% isolated headache only; nausea/
vomiting, reduced consciousness, false
localising signs, III nerve palsies
Temporal arteritis Gradual onset of temple
Continuous Temple and scalp Usually in those >55 years; unwell, jaw
pain on chewing, visual symptoms, tender
temporal arteries, elevated erythrocyte
sedimentation rate and C-reactive protein
Anterior spinocerebellar tract
Posterior spinocerebellar tract
An epileptic seizure is caused by paroxysmal electrical discharges
from either the whole brain (generalised seizure) or part of the
brain (focal seizure). A tonic–clonic seizure (convulsion) is the
most common form of generalised seizure, and typically follows a
stereotyped pattern with early loss of consciousness associated
with body stiffening (tonic phase) succeeded by rhythmical jerking
crescendoing and subsiding over 30–120 seconds (clonic phase);
this is followed by a period of unresponsiveness (often with
heavy breathing, the patient appearing to be deeply asleep) and
finally confusion as the patient reorientates (postictal phase).
The history from the patient and witnesses can help distinguish
syncope from epilepsy (Box 7.2). Focal seizures may or may not
involve loss of awareness (complete loss of consciousness is less
typical) and are characterised by whichever part of the brain is
involved: for example, a focal motor seizure arising from the motor
cortex, or temporal lobe seizures characterised by autonomic
and/or psychic symptoms, often associated with automatisms
such as lip smacking or swallowing. Functional dissociative
attacks (also known as non-epileptic or psychogenic attacks, or
pseudoseizures) are common, and may be difficult to distinguish
from epileptic seizures. These attacks are often more frequent
than epilepsy, sometimes occurring multiple times in a day, and
may last considerably longer, with symptoms waxing and waning.
Other features may include asynchronous movements, pelvic
thrusts, side-to-side rather than flexion/extension movements
and absence of postictal confusion. The widespread availability
of videophones allows witnesses to capture such events and
• If intermittent, how long do they last, and how long does
the patient remain symptom-free in between episodes?
• Was the onset sudden or gradual/evolving?
Precipitating, exacerbating or
• What was the patient doing when the symptoms
• Does anything make the symptoms better or worse,
such as time of day, menstrual cycle, posture or
Associated symptoms can aid diagnosis. For example, headache
may be associated with nausea, vomiting, photophobia (aversion
to light) and/or phonophobia (aversion to sound) in migraine;
headache with neck stiffness, fever and rash may be associated
Headache is the most common neurological symptom and
may be either primary or secondary to other pathology. Primary
• trigeminal autonomic cephalalgias (including cluster
• primary stabbing, cough, exertional or sex headache
• primary thunderclap headache
• new daily persistent headache.
Secondary (or symptomatic) headaches are less common,
but include potentially life-threatening or disabling causes such
as subarachnoid haemorrhage or temporal arteritis. One of the
key history aspects is rapidity of onset; isolated headache with
a truly abrupt onset may represent a potentially serious cause
such as subarachnoid haemorrhage or cerebral vein thrombosis,
whereas recurrent headache is much more likely to be migraine,
particularly if associated with other migrainous features like aura,
nausea and/or vomiting, photophobia and phonophobia (Box
7.1). Asking patents what they do when they have a headache
can be instructive. For example, abandoning normal tasks and
seeking a bed in a dark, quiet room suggest migraine, whereas
pacing around the room in an agitated state, or even head
banging, suggests cluster headache.
Transient loss of consciousness
Syncope is loss of consciousness due to inadequate cerebral
perfusion and is the most common cause of transient loss of
consciousness (TLOC). Vasovagal (or reflex) syncope (fainting)
is the most common type and precipitated by stimulation of the
parasympathetic nervous system, as with pain or intercurrent
illness. Exercise-related syncope, or syncope with no warning or
trigger, suggests a possible cardiac cause. TLOC on standing
is suggestive of orthostatic (postural) hypotension and may be
caused by drugs (antihypertensives or levodopa) or associated
with autonomic neuropathies, which may complicate conditions
7.2 Features that help discriminate vasovagal syncope
Feature Vasovagal syncope Seizure
Triggers Typically pain, illness,
Convulsion May occur but usually
Colour Pale/grey Flushed/cyanosed, may
Recovery Rapid, no confusion Gradual, over 30 mins;
than ischaemia include use of anticoagulation, headache, vomiting,
seizures and early reduced consciousness. Haemorrhagic stroke
is much more frequent in Asian populations. Spinal strokes are
very rare; patients typically present with abrupt bilateral paralysis,
depending on the level of spinal cord affected. The anterior
spinal artery syndrome is most common and causes loss of
motor function and pain/temperature sensation, with relative
sparing of joint position and vibration sensation below the level
Patients use ‘dizziness’ to describe many sensations. Recurrent
‘dizzy spells’ affect approximately 30% of those over 65 years
and can be due to postural hypotension, cerebrovascular disease,
cardiac arrhythmia or hyperventilation induced by anxiety and
panic. Vertigo (the illusion of movement) specifically indicates a
problem in the vestibular apparatus (peripheral) or, much less
commonly, the brain (central) (see Box 9.3 and p. 174). TIAs
do not cause isolated vertigo. Identifying a specific cause of
dizziness is often challenging but may be rewarding in some
cases, including benign paroxysmal positional vertigo (BPPV),
which is eminently treatable. As a guide, recurrent episodes of
vertigo lasting a few seconds are most likely to be due to BPPV;
vertigo lasting minutes or hours may be caused by Ménière’s
disease (with associated symptoms including hearing loss, tinnitus,
nausea and vomiting) or migrainous vertigo (with or without
Functional neurological symptoms
Many neurological symptoms are not due to disease. These
symptoms are often called ‘functional’ but other (less useful
and more pejorative) terms include psychogenic, hysterical,
somatisation or conversion disorders. Presentations include
blindness, tremor, weakness and collapsing attacks, and patients
will often describe numerous other symptoms, with fatigue,
lethargy, pain, anxiety and other mood disorders commonly
associated. Diagnosing functional symptoms requires experience
and patience (p. 363). Clues include symptoms not compatible
with disease (such as retained awareness of convulsing during
non-epileptic attacks, or being able to walk normally backwards
but not forwards), considerable variability in symptoms (such
as intermittent recovery of a hemiparesis), multiple symptoms
(often with numerous previous assessments by other specialties,
particularly gynaecology, gastroenterology, ear, nose and throat
and cardiorespiratory) and multiple unremarkable investigations,
leading to numerous different diagnoses. The size of a patient’s
case notes can sometimes be a clue in itself! Beware of labelling
symptoms as functional simply because they appear odd or
inexplicable. Like disease, most functional neurological disorders
follow recognisable patterns, so be cautious when the pattern
Symptoms that the patient has forgotten about or overlooked may
be important; for example, a history of previous visual loss (optic
neuritis) in someone presenting with numbness suggests multiple
sclerosis. Birth history and development may be significant, as
in epilepsy. Contact parents or family doctors to obtain such
information. If considering a vascular cause of neurological
symptoms, ask about important risk factors, such as other
vascular disease, hypertension, family history and smoking.
Stroke and transient ischaemic attack
A stroke is a focal neurological deficit of rapid onset that is
due to a vascular cause. A transient ischaemic attack (TIA) is
the same but symptoms resolve within 24 hours. TIAs are an
important risk factor for impending stroke and demand urgent
assessment and treatment. Hemiplegia following middle cerebral
artery occlusion is a typical example but symptoms are dictated by
the vascular territory involved. Much of the cerebral hemispheres
are supplied by the anterior circulation (the anterior and middle
cerebral arteries are derived from the internal carotid artery), while
the occipital lobes and brainstem are supplied by the posterior
(vertebrobasilar) circulation (Fig. 7.2).
A useful and simple clinical system for classifying stroke is
Isolated vertigo, amnesia or TLOC are rarely, if ever, due
to stroke. In industrialised countries about 80% of strokes are
ischaemic, the remainder haemorrhagic. Factors in the history or
examination that increase the likelihood of haemorrhage rather
Fig. 7.2 The arterial blood supply of the brain (circle of Willis).
7.3 Clinical classification of stroke
Total anterior circulation syndrome (TACS)
• Hemiparesis, hemianopia and higher cortical deficit (e.g. dysphasia
Partial anterior circulation syndrome (PACS)
• Two of the three components of a TACS
• OR isolated higher cortical deficit
• OR motor/sensory deficit more restricted than LACS (see below)
Posterior circulation syndrome (POCS)
• Ipsilateral cranial nerve palsy with contralateral motor and/or
• OR bilateral motor and/or sensory deficit
• OR disorder of conjugate eye movement
• OR cerebellar dysfunction without ipsilateral long-tract deficits
• OR isolated homonymous visual field defect
• Pure motor > 2 out of 3 of face, arm, leg
• OR pure sensory > 2 out of 3 of face, arm, leg
• OR pure sensorimotor > 2 out of 3 of face, arm, leg
Neurological assessment begins with your first contact with the
patient and continues during the history. Note facial expression,
demeanour, dress, posture, gait and speech. Mental state
examination (p. 320) and general examination (p. 20) are integral
parts of the neurological examination.
Consciousness has two main components:
• The state of consciousness depends largely on integrity of
the ascending reticular activating system, which extends
from the brainstem to the thalamus.
• The content of consciousness refers to how aware the
person is and depends on the cerebral cortex, the
thalamus and their connections.
Do not use ill-defined terms such as stuporose or obtunded.
Use the Glasgow Coma Scale (see Box 18.5), a reliable and
reproducible tool, to record conscious level.
Meningism (inflammation or irritation of the meninges) can lead
to increased resistance to passive flexion of the neck (neck
stiffness) or the extended leg (Kernig’s sign). Patients may lie with
flexed hips to ease their symptoms. Meningism suggests infection
(meningitis) or blood within the subarachnoid space (subarachnoid
haemorrhage) but can occur with non-neurological infections, such
as urinary tract infection or pneumonia. Conversely, absence of
meningism does not exclude pathology within the subarachnoid
space. In meningitis, neck stiffness has relatively low sensitivity
but higher specificity. The absence of all three signs of fever,
neck stiffness and altered mental state virtually eliminates the
diagnosis of meningitis in immunocompetent individuals.
• Position the patient supine with no pillow.
• Expose and fully extend both of the patient’s legs.
• Place your hands on either side of the patient’s head,
• Flex the patient’s head gently until their chin touches their
• Ask the patient to hold that position for 10 seconds. If
neck stiffness is present, the neck cannot be passively
flexed and you may feel spasm in the neck muscles.
• Flexion of the hips and knees in response to neck flexion
• Flex one of the patient’s legs to 90 degrees at both the
hip and the knee, with your left hand placed over the
• Extend the knee while the hip is maintained in flexion.
Look at the other leg for any reflex flexion. Kernig’s sign is
positive when extension is resisted by spasm in the
hamstrings. Kernig’s sign is absent with local causes of
neck stiffness, such as cervical spine disease or raised
can give rise to many neurological symptoms (for example,
phenytoin toxicity causing ataxia; excessive intake of simple
analgesia causing medication overuse headache; use of cocaine
Obtain a family history for at least first-degree relatives:
parents, siblings and children. In some communities, parental
consanguinity is common, increasing the risk of autosomal
recessive conditions, so you may need to enquire sensitively about
this. Many neurological disorders are caused by single-gene
defects, such as myotonic dystrophy or Huntington’s disease.
Others have important polygenic influences, as in multiple
sclerosis or migraine. Some conditions have a variety of
inheritance patterns; for example, Charcot–Marie–Tooth disease
may be autosomal dominant, autosomal recessive or X-linked.
Mitochondria uniquely have their own DNA, and abnormalities in
this DNA can cause a range of disorders that manifest in many
different systems (such as diabetes, short stature and deafness),
and may cause common neurological syndromes such as migraine
or epilepsy. Some diseases, such as Parkinson’s or motor
neurone disease, may be either due to single-gene disorders
Social circumstances are relevant. How are patients coping with
their symptoms? Are they able to work and drive? What are their
support circumstances, and are these adequate?
Alcohol is the most common neurological toxin and damages
both the CNS (ataxia, seizures, dementia) and the PNS
(neuropathy). Poor diet with vitamin deficiency may compound
these problems and is relevant in areas affected by famine and
alcoholism or dietary exclusion. Vegetarians may be susceptible
to vitamin B12 deficiency. Recreational drugs may affect the
nervous system; for example, nitrous oxide inhalation causes
subacute combined degeneration of the cord due to dysfunction
of the vitamin B12 pathway, and smoking contributes to vascular
and malignant disease. Always consider sexually transmitted
or blood-borne infection, such as human immunodeficiency
virus (HIV) or syphilis, as both can cause a wide range of
neurological symptoms and are treatable. A travel history may
give clues to the underlying diagnosis, such as Lyme disease
(facial palsy), neurocysticercosis (brain lesions and epilepsy) or
Occupational factors are relevant to several neurological disorders.
For example, toxic peripheral neuropathy, due to exposure to
heavy or organic metals like lead, causes a motor neuropathy;
manganese causes Parkinsonism. Some neurological diagnoses
may adversely affect occupation, such as epilepsy in anyone who
needs to drive or operate dangerous machinery. For patients with
cognitive disorders, particularly dementias, it may be necessary
to advise on whether to stop working.
The physical examination • 125
Dysphonia usually results from either vocal cord pathology,
as in laryngitis, or damage to the vagal (X) nerve supply to
the vocal cords (recurrent laryngeal nerve). Inability to abduct
one of the vocal cords leads to a ‘bovine’ (and ineffective)
Dysphasia is a disturbance of language resulting in abnormalities
of speech production and/or understanding. It may involve other
language symptoms, such as writing and/or reading problems,
unlike dysarthria and dysphonia.
The language areas are located in the dominant cerebral
hemisphere, which is the left in almost all right-handed people
Broca’s area (inferior frontal region) is concerned with word
production and language expression.
Wernicke’s area (superior posterior temporal lobe) is the
principal area for comprehension of spoken language. Adjacent
regions of the parietal lobe are involved in understanding written
The arcuate fasciculus connects Broca’s and Wernicke’s areas.
• During spontaneous speech, listen to the fluency and
appropriateness of the content, particularly paraphasias
(incorrect words) and neologisms (nonsense or
• Show the patient a common object, such as a coin or
• Give a simple three-stage command, such as ‘Pick up this
piece of paper, fold it in half and place it under the book.’
• Ask the patient to repeat a simple sentence, such as
• Ask the patient to read a passage from a newspaper.
• Ask the patient to write a sentence; examine the
Expressive (motor) dysphasia results from damage to Broca’s
area. It is characterised by reduced verbal output with non-fluent
speech and errors of grammar and syntax. Comprehension is
Receptive (sensory) dysphasia occurs due to dysfunction in
Wernicke’s area. There is poor comprehension, and although
speech is fluent, it may be meaningless and contain paraphasias
Global dysphasia is a combination of expressive and receptive
difficulties caused by involvement of both areas.
Dysphasia (a focal sign) is frequently misdiagnosed as
confusion (non-focal). Always consider dysphasia before assuming
confusion, as this fundamentally alters the differential diagnosis
Dominant parietal lobe lesions affecting the supramarginal gyrus
may cause dyslexia (difficulty comprehending written language),
dyscalculia (problems with simple addition and subtraction) and
dysgraphia (impairment of writing). Gerstmann’s syndrome is the
combination of dysgraphia, dyscalculia, finger agnosia (inability
to recognise the fingers) and inability to distinguish left from
right. It localises to the left parietal lobe in the region of the
Dysarthria refers to slurred or ‘strangulated’ speech caused by
articulation problems due to a motor deficit.
Dysphonia describes loss of volume caused by laryngeal
• Listen to the patient’s spontaneous speech, noting
• Ask the patient to repeat phrases such as ‘yellow lorry’ to
test lingual (tongue) sounds and ‘baby hippopotamus’ for
labial (lip) sounds, then a tongue twister such as ‘The Leith
• Ask the patient to count to 30 to assess fatigue.
• Ask the patient to cough and to say ‘Ah’; observe the soft
Disturbed articulation (dysarthria) may result from localised
lesions of the tongue, lips or mouth, ill-fitting dentures or
neurological dysfunction. This may be due to pathology anywhere
in the upper and lower motor neurones, cerebellum, extrapyramidal
system, or nerve, muscle or neuromuscular junction.
Bilateral upper motor neurone lesions of the corticobulbar tracts
cause a pseudobulbar dysarthria, characterised by a slow, harsh,
strangulated speech with difficulty pronouncing consonants, and
may be accompanied by a brisk jaw jerk and emotional lability.
The tongue is contracted and stiff.
Bulbar palsy (see Box 7.5 later) results from bilateral lower motor
neurone lesions affecting the same group of cranial nerves (IX, X,
XI, XII). The nature of the speech disturbance is determined by the
specific nerves and muscles involved. Weakness of the tongue
results in difficulty with lingual sounds, while palatal weakness
gives a nasal quality to the speech.
Cerebellar dysarthria may be slow and slurred, similar to alcohol
intoxication. Myasthenia gravis causes fatiguing speech, becoming
increasing nasal, and may disappear altogether. Parkinsonism may
cause dysarthria and dysphonia, with a low-volume, monotonous
voice, words running into each other (festination of speech), and
Fig. 7.3 Testing for meningeal irritation: Kernig’s sign.
cortical function can be difficult and time-consuming but is essential
in patients with cognitive symptoms. There are various tools, all
primarily developed as screening and assessment tools for dementia.
For the bedside the Mini-Mental State Examination (MMSE) and
Montreal Cognitive Assessment (MoCA) are quick to administer,
while the Addenbrooke’s Cognitive Examination is more detailed
but takes longer. None of these bedside tests is a substitute for
detailed neuropsychological assessment. The assessment of
cognitive function is covered in more detail on page 323.
Thinking, emotions, language, behaviour, planning and initiation of
movements, and perception of sensory information are functions of
the cerebral cortex and are central to awareness of, and interaction
with, the environment. Certain cortical areas are associated with
specific functions, so particular patterns of dysfunction can help
localise the site of pathology (Fig. 7.4A). Assessment of higher
M a s t i c a t i o n S a l i v a t i o n V o c a l i s a t i o n
B Fig. 7.4 Cortical function. A Features of localised cerebral
lesions. B Somatotopic homunculus.
The 12 pairs of cranial nerves (with the exception of the olfactory
(I) pair) arise from the brainstem (Fig. 7.5 and Box 7.4). Cranial
nerves II, III, IV and VI relate to the eye (Ch. 8) and the VIII nerve
to hearing and balance (Ch. 9).
The olfactory nerve conveys the sense of smell.
Bipolar cells in the olfactory bulb form olfactory filaments with small
receptors projecting through the cribriform plate high in the nasal
cavity. These cells synapse with second-order neurones, which
project centrally via the olfactory tract to the medial temporal
Bedside testing of smell is of limited clinical value, and rarely
performed, although objective ‘scratch and sniff’ test cards,
such as the University of Pennsylvania Smell Identification
Test (UPSIT), are available. You can ask patients if they think
their sense of smell is normal, although self-reporting can be
The posterior part of the frontal lobe is the motor strip (precentral
gyrus), which controls voluntary movement. The motor strip
is organised somatotopically (Fig. 7.4B). The area anterior
to the precentral gyrus is concerned with personality, social
behaviour, emotions, cognition and expressive language, and
contains the frontal eye fields and cortical centre for micturition
Frontal lobe damage may cause:
• personality and behaviour changes, such as apathy or
• loss of emotional responsiveness, or emotional lability
• cognitive impairments, such as memory, attention and
• dysphasia (dominant hemisphere)
• conjugate gaze deviation to the side of the lesion
• primitive reflexes, such as grasp
• focal motor seizures (motor strip).
The temporal lobe contains the primary auditory cortex, Wernicke’s
area and parts of the limbic system. The latter is crucially important
in memory, emotion and smell appreciation. The temporal lobe
also contains the lower fibres of the optic radiation and the area
Temporal lobe dysfunction may cause:
• focal seizures with psychic symptoms
• contralateral upper quadrantanopia (see Fig. 8.5(4))
• receptive dysphasia (dominant hemisphere).
The postcentral gyrus (sensory strip) is the most anterior part
of the parietal lobe and is the principal destination of conscious
sensations. The upper fibres of the optic radiation pass through
it. The dominant hemisphere contains aspects of language
function and the non-dominant lobe is concerned with spatial
Features of parietal lobe dysfunction include:
• cortical sensory impairments
• contralateral lower quadrantanopia (see Fig. 8.5(5))
• dyslexia, dyscalculia, dysgraphia
• apraxia (an inability to carry out complex tasks despite
having an intact sensory and motor system)
• focal sensory seizures (postcentral gyrus)
• visuospatial disturbance (non-dominant parietal lobe).
The occipital lobe blends with the temporal and parietal lobes
and forms the posterior part of the cerebral cortex. Its main
function is analysis of visual information.
Occipital lobe damage may cause:
• visual field defects: hemianopia (loss of part of a visual
field) or scotoma (blind spot) (see Fig. 8.5(6)).
• visual agnosia: the inability to recognise visual stimuli
• disturbances of visual perception, such as macropsia
(seeing things larger) or micropsia (seeing things smaller)
7.4 Summary of the 12 cranial nerves
Nerve Examination Abnormalities/symptoms
Optic disc and retinal changes
Strabismus, diplopia, nystagmus
Impairment, distortion or loss
Increase in upper motor neurone
IX Pharyngeal sensation Not routinely tested
X Palate movements Unilateral or bilateral impairment
ganglion, the V nerve passes to the pons. From here, pain and
temperature pathways descend to the C2 segment of the spinal
cord, so ipsilateral facial numbness may occur with cervical cord
There are three major branches of V (Fig. 7.6):
• mandibular (V3): sensory and motor.
Fig. 7.6 The sensory distribution of the three divisions of the
trigeminal nerve. 1, Ophthalmic division. 2, Maxillary division.
Hypoglossal nerve (hypoglossal canal)
Mandibular division of trigeminal
Abducens nerve (inferior petrosal sinus)
cerebelli and the roof of the trigeminal cave have been removed.
Hyposmia or anosmia (reduction or loss of the sense of
smell) may result from upper respiratory infection, sinus
disease, damage to the olfactory filaments after head injury or
infection, local compression (by olfactory groove meningioma,
for example; see Fig. 7.29C) or invasion by basal skull
tumours. Disturbance of smell may also occur very early in
Parkinson’s and Alzheimer’s diseases. Patients often note
hypogeusia/ageusia (altered taste) with anosmia too, as taste
is crucially influenced by the sense of smell.
Parosmia is the perception of pleasant odours as
unpleasant; it may occur with head trauma or sinus
infection, or be an adverse effect of drugs. Olfactory
hallucinations may occur in Alzheimer’s disease and focal
Optic (II), oculomotor (III), trochlear (IV)
The V nerve conveys sensation from the face, mouth and part of
the dura, and provides motor supply to the muscles of mastication.
The cell bodies of the sensory fibres are located in the trigeminal
(Gasserian) ganglion, which lies in a cavity (Meckel’s cave) in
the petrous temporal dura (see Fig. 7.5). From the trigeminal
• Ask the patient to let their mouth hang loosely open.
• Place your forefinger in the midline between lower lip and
• Percuss your finger gently with the tendon hammer in a
downward direction (Fig. 7.8), noting any reflex closing of
• An absent, or just present, reflex is normal. A brisk jaw
jerk occurs in pseudobulbar palsy (Box 7.5).
The ophthalmic branch leaves the ganglion and passes forward
to the superior orbital fissure via the wall of the cavernous sinus
(see Fig. 8.3). In addition to the skin of the upper nose, upper
eyelid, forehead and scalp, V1 supplies sensation to the eye
(cornea and conjunctiva) and the mucous membranes of the
sphenoidal and ethmoid sinuses and upper nasal cavity.
The maxillary branch (V2) passes from the ganglion via the
cavernous sinus to leave the skull by the foramen rotundum.
It contains sensory fibres from the mucous membranes of
the upper mouth, roof of pharynx, gums, teeth and palate
of the upper jaw and the maxillary, sphenoidal and ethmoid
The mandibular branch (V3) exits the skull via the foramen ovale
and supplies the floor of the mouth, sensation (but not taste)
to the anterior two-thirds of the tongue, the gums and teeth of
the lower jaw, mucosa of the cheek and the temporomandibular
joint, in addition to the skin of the lower lips and jaw area, but
not the angle of the jaw (see Fig. 7.6).
The motor fibres of V run in the mandibular branch (V3) and
innervate the muscles of mastication: temporalis, masseter and
medial and lateral pterygoids.
Four aspects need to be assessed: sensory, motor and two
• Ask the patient to close their eyes and say ‘yes’ each time
they feel a light touch (you use a cotton-wool tip for this
test). Do this in the areas of V1, V2 and V3.
• Repeat using a fresh neurological pin, such as a Neurotip,
• Compare both sides. If you identify an area of reduced
sensation, map it out. Does it conform to the distribution
of the trigeminal nerve or branches? Remember the angle
of the jaw is served by C2 and not the trigeminal nerve,
but V1 extends towards the vertex (see Fig. 7.6).
• ‘Nasal tickle’ test: use a wisp of cotton wool to ‘tickle’ the
inside of each nostril and ask the patient to compare. The
normal result is an unpleasant sensation easily appreciated
• Inspect for wasting of the muscles of mastication (most
• Ask the patient to clench their teeth; feel the masseters,
• Ask the patient to open their jaw and note any deviation;
the jaw may deviate to the paralysed side due to
contraction of the intact contralateral pterygoid muscle.
Routine testing of the corneal reflex is unnecessary, but may
be relevant when the history suggests a lesion localising to
the brainstem or cranial nerves V, VII or VIII. The afferent limb
is via the trigeminal nerve, the efferent limb via the facial
• Explain to the patient what you are going to do and ask
them to remove their contact lenses, if relevant.
• Gently depress the lower eyelid while the patient looks up.
• Lightly touch the lateral edge of the cornea with a wisp of
• Look for both direct and consensual blinking.
Fig. 7.7 Testing the corneal reflex. The cotton-wool wisp should touch
the cornea overlying the iris, not the conjunctiva, and avoid visual stimulus.
Fig. 7.8 Eliciting the jaw jerk.
7.5 Comparison of bulbar and pseudobulbar palsy
Bulbar palsy Pseudobulbar palsy
Level of motor lesion Lower motor
Speech Dysarthria Dysarthria and dysphonia
Swallowing Dysphagia Dysphagia
Emotional lability Absent May be present
from the lateral pontomedullary junction in close association with
the VIII nerve (Fig. 7.11); together they enter the internal acoustic
meatus (see Fig. 7.5). At the lateral end of the meatus the VII
nerve continues in the facial canal within the temporal bone,
exiting the skull via the stylomastoid foramen. Passing through
the parotid gland, it gives off its terminal branches. In its course
in the facial canal it gives off branches to the stapedius muscle
and its parasympathetic fibres, as well as being joined by the
taste fibres of the chorda tympani (see Fig. 7.10).
Examination is usually confined to motor function; taste is
• Inspect the face for asymmetry or differences in blinking or
eye closure on one side. Note that minor facial asymmetry
is common and rarely pathological.
• Watch for spontaneous or involuntary movement.
• For the following actions it is often easiest to demonstrate
the actions yourself and ask the patient to copy you,
• Ask the patient to raise their eyebrows and observe for
symmetrical wrinkling of the forehead (frontalis muscle).
• Ask the patient to screw their eyes tightly shut and resist
you opening them (orbicularis oculi).
• Ask the patient to bare their teeth (orbicularis oris).
• Ask the patient to blow out their cheeks with their mouth
closed (buccinators and orbicularis oris).
Sensory symptoms include facial numbness and pain. Unilateral
loss of sensation in one or more branches of the V nerve may
result from direct injury in association with facial fractures
(particularly V2), local invasion by cancer or Sjögren’s syndrome.
Lesions in the cavernous sinus often cause loss of the corneal
reflex and V1 or V2 cutaneous sensory loss. Cranial nerves III, IV
and VI may also be involved (see Fig. 8.3). Trigeminal neuralgia
causes severe, lancinating pain, typically in the distribution of V2
or V3. Reactivation of herpes varicella zoster virus (chickenpox)
can affect any sensory nerve, but typically either V1 or a thoracic
dermatome (Fig. 7.9). In herpes zoster ophthalmicus (affecting V1)
there is a risk of sight-threatening complications. Hutchinson’s
sign, vesicles on the side or tip of the nose, may be present.
Clinically significant weakness of the muscles of mastication
is unusual but may occur in myasthenia gravis, with fatigable
The facial nerve supplies the muscles of facial expression (frontalis,
orbicularis oculi, buccinators, orbicularis oris and platysma) and
carries parasympathetic fibres to the lacrimal, submandibular and
sublingual salivary glands (via nervus intermedius). It receives
taste sensation from the anterior two-thirds of the tongue (via
the chorda tympani; Fig. 7.10).
From its motor nucleus in the lower pons, fibres of the VII nerve
pass back to loop around the VI nerve nucleus before emerging
spinal root left C5. D Thoracic spinal root right T8.
angle tumours (including acoustic neuroma), trauma and
parotid tumours. Synkinesis (involuntary muscle contraction
accompanying a voluntary movement: most commonly, twitching
of the corner of the mouth with ipsilateral blinking) is a sign of
aberrant reinnervation and may be seen in recovering lower
In unilateral VII nerve upper motor neurone lesions, weakness
is marked in the lower facial muscles with relative sparing of the
upper face. This is because there is bilateral cortical innervation
of the upper facial muscles. The nasolabial fold may be flattened
and the corner of the mouth drooped, but eye closure is
usually preserved (Fig. 7.12B). Hemifacial spasm presents with
synchronised twitching of the ipsilateral eye and mouth.
Bilateral facial palsies are less common, but occasionally occur,
as in Guillain–Barré syndrome, sarcoidosis, or infection such as
Lyme disease, HIV or leprosy. Facial weakness, especially with
respect to eye closure, can also be found in some congenital
myopathies (facioscapulohumeral or myotonic dystrophies).
Distinct from VII nerve palsies, Parkinson’s disease can cause loss
of spontaneous facial movements, including a slowed blink rate,
and involuntary facial movements (levodopa-induced dyskinesias)
may complicate advanced disease.
Involuntary emotional movements, such as spontaneous
smiling, have different pathways and may be preserved in the
Vestibulocochlear (VIII) nerve
Glossopharyngeal (IX) and vagus (X) nerves
The IX and X nerves have an intimate anatomical relationship.
Both contain sensory, motor and autonomic components. The
glossopharyngeal (IX) nerve mainly carries sensation from the
pharynx and tonsils, and sensation and taste from the posterior
one-third of the tongue. The IX nerve also supplies the carotid
chemoreceptors. The vagus (X) nerve carries important sensory
In a unilateral lower motor neurone VII nerve lesion, there is
weakness of both upper and lower facial muscles. Bell’s palsy
is the term used to describe an idiopathic acute lower motor
neurone VII nerve paralysis, often preceded by mastoid pain. It
may be associated with impairment of taste and hyperacusis
(high-pitched sounds appearing unpleasantly louder than normal).
Bell’s phenomenon occurs when a patient closes their eyes:
as eye closure is incomplete the globe can be seen to roll
upwards, to avoid corneal exposure (Fig. 7.12A). Ramsay Hunt
syndrome occurs in herpes zoster infection of the geniculate (facial)
ganglion. This produces a severe lower motor neurone facial
palsy, ipsilateral loss of taste and buccal ulceration, and a painful
vesicular eruption in the external auditory meatus. Other causes
of a lower motor neurone VII lesion include cerebellopontine
Fig. 7.10 Component fibres of the facial nerve and their peripheral distribution.
Fig. 7.11 Lesions of the pons. Lesions at (1) may result in ipsilateral VI
and VII nerve palsies and contralateral hemiplegia. At (2) ipsilateral
cerebellar signs and impaired sensation on the ipsilateral side of the face
and on the contralateral side of the body may occur.
Isolated unilateral IX nerve lesions are rare. Unilateral X nerve
damage leads to ipsilateral reduced elevation of the soft palate,
which may cause deviation of the uvula (away from the side of
the lesion) when the patient says ‘Ah’. Unilateral lesions of IX and
X are most commonly caused by strokes, skull-base fractures or
tumours. Damage to the recurrent laryngeal branch of the X nerve
due to lung cancer, thyroid surgery, mediastinal tumours and
aortic arch aneurysms causes dysphonia and a ‘bovine’ cough.
Bilateral X nerve lesions cause dysphagia and dysarthria, and may
be due to lesions at the upper motor neurone level (pseudobulbar
palsy) or lower motor neurone level (bulbar palsy; see Box 7.5).
Less severe cases can result in nasal regurgitation of fluids and
nasal air escape when the cheeks are puffed out (dysarthria and
nasal escape are often evident during history taking). Always
consider myasthenia gravis in patients with symptoms of bulbar
dysfunction, even if the examination seems normal.
information but also innervates upper pharyngeal and laryngeal
muscles. The main functions of IX and X that can be tested
clinically are swallowing, phonation/articulation and sensation
from the pharynx/larynx. In the thorax and abdomen, the vagus
(X) nerve receives sensory fibres from the lungs and carries
parasympathetic fibres to the lungs, heart and abdominal viscera.
Both nerves arise as several roots from the lateral medulla and
leave the skull together via the jugular foramen (see Fig. 7.5). The
IX nerve passes down and forwards to supply the stylopharyngeus
muscle, the mucosa of the pharynx, the tonsils and the posterior
one-third of the tongue, and sends parasympathetic fibres to the
parotid gland. The X nerve courses down in the carotid sheath
into the thorax, giving off several branches, including pharyngeal
and recurrent laryngeal branches, which provide motor supply
to the pharyngeal, soft palate and laryngeal muscles. The main
nuclei of these nerves in the medulla are the nucleus ambiguus
(motor), the dorsal motor vagal nucleus (parasympathetic) and
the solitary nucleus (visceral sensation; Fig. 7.13).
• Assess the patient’s speech for dysarthria or dysphonia
• Ask them to say ‘Ah’. Look at the movements of the
palate and uvula using a torch. Normally, both sides of the
palate elevate symmetrically and the uvula remains in the
• Ask the patient to puff out their cheeks with their lips
tightly closed. Listen for air escaping from the nose. For
the cheeks to puff out, the palate must elevate and
occlude the nasopharynx. If palatal movement is weak, air
will escape audibly through the nose.
• Ask the patient to cough; assess the strength of the
• Testing pharyngeal sensation and the gag reflex is
unpleasant and has poor predictive value for aspiration.
Instead, and in fully conscious patients only, use the
swallow test. Administer 3 teaspoons of water and
observe for absent swallow, cough or delayed cough, or
change in voice quality after each teaspoon. If there are no
problems, observe again while the patient swallows a
B Right-sided upper motor neurone lesion.
Taste from posterior one-third
Fig. 7.13 The lower cranial nerves: glossopharyngeal (IX), vagus (X)
• Ask the patient to put out their tongue. Look for deviation
• Ask the patient to move their tongue quickly from side to
• Test power by asking the patient to press their tongue
against the inside of each cheek in turn while you press
from the outside with your finger.
• Assess speech by asking the patient to say ‘yellow lorry’.
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