1. Cranial Nerve Lesions – common patterns of presentation CN III, IV & VI palsy
- Site of lesion:
Horner’s syndrome - Symptoms: ptosis, miosis, narrowed i) within cavernous sinus – CN III, IV, V & VI palsies
palpebral fissure, anhidrosis, flushing & ii) entrance to orbit (superior orbital fissure)
sinking in of eyeball iii) within orbit
- Causes: Ipsilateral brainstem lesion,
Cervical cord lesion, CN V palsy
Cervical sympathetic chain injury, Ganglion / Sensory root lesion
Cervical rib, – total loss of sensation in all 3 divisions
Cancerous involvement of stellate
ganglion, Post-ganglionic lesion
Pancost tumour – Total loss of sensation in ONE division (usu ophthalmic division
in a/w CN III, IV & VI palsies too due to lesion in cavernous sinus
CN II palsy - Homonymous hemianopia – optic tract/radiation
lesion Brainstem / Upper spinal cord lesion
- Bitemporal hemianopia – optic chiasmal lesion eg - Symptoms: dissociated sensory loss of face – loss of
pituitary gland tumour temp & pain but retention of touch and
proprioception sensations of face
CN III palsy - Symptoms: ‘Down & out’ pupils, ptosis, papillary
dilatation, loss of papillary light reflex, loss of Unilateral CN V, VII & VIII palsy
accommodation - cerebellopontine angle lesion eg tumour
- Site of lesion – oculomotor Nc within midbrain, or
along its peripheral course
CN VI palsy - Symptom: unable to abduct eye
- Site of lesion: lesion of abducens Nc in pons, or lesion
along peripheral course
*However, it is a Non-localising sign as it has
a long course and is easily affected by raised
ICP due to lesions in any part of the brain
- If bilateral: consider raised ICP, trauma, Wernicke’s
encephalopathy (triad of ophthalmoplegia,
confusion & ataxia) & mononeuritis multiples
CN VII palsy - UMN vs LMN lesion: paradoxical sparing of upper CN IX-XI palsy - Symptoms: dysphonia, unilat weakness, wasting &
parts of face in UMN lesion fasciculation of tongue, depression of gag
- Site of lesion - Internal acoustic meatus injury by reflex, unilat wasting of SCM & trapezius
tumour, Bell’s palsy (facial n. canal), parotid muscles
gland tumour/Sx - Site of lesion: along their peripheral course as they
exit the skull together at the foramina of skull
Pattern Causes base (jugular foramen)
UMN lesion Vascular lesions
Tumours Pseudobulbar palsy (bilat UMN lesion of CN IX, X & XII)
LMN lesion Pontine lesion – a/w CN V & VI lesions - degeneration of corticobulbar tracts, which project to:
Post. Fossa lesions i) Nc ambigus → cranial root of CN XI →vagus n.
o Acoustic neuromas → soft palate, pharynx & larynx
o Meningiomas ii) Hypoglossal Nc → tongue
Petrous temporal bone – - Symptoms: dysphonia, dysphagia, dysarthria, tongue weakness
o Bell’s palsy (commonest cause of CN VII palsy) & spasticity
o Ramsay Hunt syndrome Bulbar palsy (bilat LMN lesion of CN IX, X & XII)
o Fractures - degeneration of Nc ambigus & hypoglossal Nc themselves
o Ottitis media - Symptoms: dysphonia, dysarthria, dysphagia, wasting
Parotid gland – tumour, surgery fasciculation & weakness of tongue
Bilateral Guillain-Barre syndrome
Pseudobulbar Bulbar
Gag reflex ↑/N Absent
Bell’s palsy - acute unilat inflammatory lesion of CN VII along its Tongue Spastic Wasted, fasciculations
course through the skull Jaw jerk ↑ Absent / N
- Symptoms: ear pain, unilat facial muscle paralysis, Speech Spastic dysarthria Nasal
absent corneal reflex, hyperacusis Other Bilat limb UMN signs Signs of underlying cause
(exceptional acute sense of hearing) of Labile emotions eg limb fasciculations
affected side, loss of taste in ant 2/3 of Normal emotions
tongue Causes BIlat CVA (eg both internal Motor neurone disease
Ramsay-Hunt syndrome – VZV associated Bell’s palsy with vesicular capsules) Guillain-Barre syndrome
rash in ext acoustic canal & mucous memb of oropharynx
Multiple sclerosis Polio
Motor neurone disease Brainstem infarction
Acoustic Neuroma - CN VII neuroma
- Symptoms: dizziness, deafness, ataxia, CN V-VII
palsy & paralysis of limbs
- a/w neurofibromatosis

2. Causes of Multiple CN palsies Interpretation of Peripheral Nervous System Examination
1. Guillain-Barre syndrome – sparing of sensory nerves
2. Mononeuritis Multiplex (rare) eg DM Site of Lesion:
3. Brainstem lesions UMN vs LMN lesion
– usu due to vascular disease causing crossed sensory UMN: Cortical vs brainstem vs cord lesions
or motor paralysis (ie CN signs on one side and LMN: Radiculopathy vs plexus lesion vs major nerve trunk lesion
contralat long tract signs) Others: Peripheral neuropathy (eg glove & stocking neuropathy of
- Brainstem tumour may also have similar signs DM), parkinsonism
4. NPC
5. Arnold-Chiari malformation Tone LMN lesion – Fasciculations, wasting & hypotonia
6. Paget’s disease UMN lesion – Hypertonia on knee lift and clonus
7. Chronic meningitis Parkinsonism – cog-wheeling & lead-pipe rigidity
8. Trauma
Reflex LMN lesion – Hyporeflexia
Causes of Nystagmus UMN lesion – Hyperreflexia
Horizontal Radiculopathy – Hyporeflexia in corresponding nerve root region
1. Vestibular lesion Major nerve trunk lesion – Hyporeflexia of distribution of nerve
– if acute, saccadic movt away from side of lesion. roots contributing to nerve trunk
– If chronic, saccadic movt towards side of lesion Motor nerve problem (neuropathy)
2. Cerebellar lesion – saccades to side of lesion of unilat
3. Toxic – phenytoin, alcohol Power Major nerve trunk lesion – reduced power in distribution of nerve
4. Intranuclear ophthalmoplegia (lesion of medial longitudinal roots contributing to nerve trunk
fasciculus) – nystagmus in abducting eye + failure of adduction of Radiculopathy – decrease power in affected nerve roots
contralat (affected) side.
Vertical Sensation Peripheral neuropathy – glove & stocking distribution
1. Brainstem lesion Major nerve trunk – sensation loss over sensory
2. Drugs – Phenytoin, alcohol distribution of nerve trunk
Radiculopathy – dermatomal distribution of sensory
loss
Pain & Temp – Second-order neurons of the Spinothalamic tract
decussate within one segment of their origin and ascend
contralaterally.
Vibration, proprioception & light touch – Axons of Pri afferent
neurons ascend in Dorsal Column ipsilaterally and terminate on
Second-order neurons in the medulla oblongata. Second-order
neurons decussate in the medulla
Screening test for Upper Limb Examination Radial Nerve Palsy (C5-8)
- Wrist drop
1) Extend arm outwards - Weak wrist extension
- Proximal myopathy? - Weak elbow extension if lesion level is high
- Cerebellar signs – pronator drift? - Thumb: weak extension of thumb
2) Clench fist Medial Nerve Palsy (C6-T1)
- Slow clenching – Myotonic Dystrophy - Simian hands
- Weak flexion of index finger – Median nerve palsy - Flattened thenar eminence (thumb side)
- Wrist lesion & above – unable to abduct thumb (ie point upwards)
3) Turn hand around - Lesion in cubital fossa – index finger unable to flex on clasping
hands together
4) Flex fists - Thumb: weak abduction of thumb; weak opposition function of
- Test of Median Nerve motor function - Weak flexion @ wrist thumb
accompanied by adduction
Ulnar Nerve Palsy (C8-T1)
5) Extend fists - Claw hand and ulnar paradox
- Test of Radial Nerve function - Flattened
- Froment’s sign – grasp paper btwn thumb and lat aspect of index
6) Unclench fists finger – affected thumb will flex
- Slow unclenching – Myotonic Dystrophy - Weak interreosei muscles – unable to grasp paper btwn fingers;
- Test of Radial nerve motor function of finger extension weak spreading of fingers
- Claw hand – Ulnar nerve palsy - Thumb: weak adduction of thumb

3. Femoral Nerve Palsy (L2-4)
- Slight hip flexion weakness
- Weak knee extension
- Absent knee jerk
- Sensory loss over inner thigh & leg
Sciatic Nerve Palsy (L4-S2)
- Loss of power below knee – Weak knee flexion & Foot drop
- Absent ankle jerk
- Absent plantar response
- Sensory loss over lateral & posterior calf and foot
Common Peroneal Nerve Palsy (L4-S1)
- Foot drop – weak dorsiflexion & eversion of foot
- Intact reflexes
- Minimal sensory loss over lateral aspect of dorsum of foot
Digitally signed by DR WANA HLA SHWE
DN: cn=DR WANA HLA SHWE, c=MY,
o=UCSI University, School of Medicine, KT-
Campus, Terengganu, ou=Internal Medicine
Group, email=wunna.hlashwe@gmail.com
Reason: This document is for UCSI year 4
students.
Date: 2009.02.24 14:21:14 +08'00'