Look at this patient's face.
Examine the cranial nerves.
· Onset: whether abrupt followed by worsening over the following day (Bell's palsy).
· Pain preceding or accompanying the weakness (Bell's palsy).
· The face itself feels stiff and pulled to one side.
· Ipsilateral restriction of eye closure.
· Difficulty with eating.
· Disturbance of taste (due to chorda tympani fibres).
· Hyperacusis (involvement of stapedius muscle in the inner ear).
· Weakness of muscles of one half of the face - patient is unable to screw her eyes tightly shut or move the angle of the mouth on the affected
· Loss offacial expression.
· Widened palpebra] fissure.
Proceed as follows':
· Look for the following when the patient is unaware of being observed: -Flatter nasolabial folds on the affected side.
-Mouth on the affected side droops and participates manifestly less while talking. -The eyelid on the affected side closes just after the opposite eyelid.
· Look at the external auditory meatus for herpes zoster (Ramsay Hunt syndrome).
· Look for parotid gland enlargement.
· Examine for taste (loss of taste with the involvement of chorda tympani).
· Check for hearing (for hyperacusis resulting from involvement of the nerve to stapedius muscle).
* Examine the tympanic membrane for otitis media.
· Tell the examiner that you would like to do the following: -Test the urine for sugar (diabetes).
The patient has lower motor neuron seventh cranial nerve palsy (lesion) which is idiopathic (aetiology). She is distressed because
the condition causes severe dis-figurement while talking (functional status).
How would you differentiate between upper and lower motor neuron palsy?
In lower motor neuron palsy the whole hall' of the face on the affected side is involved. In upper motor neuron palsy the upper half of
the face (the forehead) is spared.
What are the causes of bilateral facial nerve palsy?
· Guillain-Barre syndrome (see pp 243-4).
· Sarcoidosis in the form of uveoparotid fever (Heerfordt's disease).
· Melkersson-Rosenthal syndrome, which is a triad of facial palsy, recurrent facial oedema and plication of the tongue
(Hygiea(Stockholm) 1928; 90: 737-41; Z Neurol Psychiatr 1931; 131:475-501 ).
Note. Myasthenia may mimic bilateral facial nerve palsy.
What are the causes of unilateral facial nerve palsy?
Lower motor neuron (all the muscles of one half of the face are affected):
· Bell's palsy (idiopathic). Recent studies using a polymerase chain reaction have implicated herpes simplex viral infection in
Bell's palsy. The incidence of Bell's palsy is 23 per 100 000 individuals per year or about 1 in 60-70 individuals per year. Men
and women are equally affected and the peak incidence is between the ages of 10 and 40. Both the right and left sides are
affected with equal frequency.
· Herpes zoster.
· Cerebellopontine angle tumours.
· Parotid tumours.
· Old polio.
· Otitis media.
· Skull fracture.
Upper motor neuron (forehead spared):
· Stroke (hemiplegia).
Is the facial nerve a motor nerve or a sensory nerve?
The facial nerve is predominantly a motor nerve and supplies all muscles concerned with facial expression and the stapedius
muscle. Uncommonly, it may have a sensory component which is small - the nervus intermedius of Wrisberg. It conveys
tastesensation from the anterior two thirds of the tongue and, probably, cutaneous impulses from the anterior wall of the external
What do you know of nervus intermedius?
The nervus intermedius or pars intermedia of Wrisberg is the sensory or the para-sympathetic root of the facial nerve, and is lateral
and inferior to the motor root. Inside the internal auditory meatus it lies between the motor root and the eighth cranial nerve. The
sensory cells are located in the geniculate ganglion (at the bend of the facial nerve in the facial canal) and their nerve fibres enter
the pons with the motor root. The geniculate ganglion is continued distally as the chorda tympani, which carries taste and
preganglionic parasympathetic fibres. This nerve consists of contributions from three areas:
· Superior salivary nucleus (in the pons) supplies secretory fibres to the glands.
· Gustatory or solitary nucleus (in the medulla) receives taste fibres via the chorda tympani.
· Dorsal part of the trigeminal nerve receives cutaneous sensation from the external auditory meatus and the skin behind the ear
(distributed with the facial nerve proper).
How would you manage Bell's palsy?
About 50-60% of patients recover spontaneously without deficits, others have con-siderable improvement and about 10% have
permanent residual deficits. Therefore many physicians tend to initiate treatment with steroids only in those with clinically complete
deficit or when there is severe pain. Treatment includes:
· Physiotherapy: massage, electrical stimulation, splint to prevent drooping of the lower part of the face.
· Protection of the eye with lubricating eye drops and a patch during sleep.
· A short course of dexamethasone 2 mg three times a day for 5 days and tapered over the next 5 days (should be given within
48 hours of onset).
· Aciclovir-prednisone is more effective in improving volitional muscle activity and in preventing partial nerve degeneration as
compared to placebo-prednisone treatment (Ann Otol Rhinol Laryngol 1996; 105:371 ).
What are the branches of the facial nerve?
· Greater superficial petrosal nerve (supplies lacrimal, nasal and palatine glands). · Nerve to stapedius muscle.
· Chorda tympani (supplies taste to anterior two thirds of tongue, submaxillary and sublingual glands).
· Motor branches (exit from the stylomastoid foramen).
How would you localize facial nerve palsy?
· Involvement of the nuclei in the pons - associated ipsilateral sixth nerve palsy. · Cerebellopontine angle lesion - associated fifth and
eighth nerve involvement.
· Lesion in the bony canal loss of taste (carried by the lingual nerve) and hyperacusis (due to involvement of the nerve to
Mention reflexes involving the facial nerve.
· Corneal reflex (see p. 108).
· Palmomental reflex (see p. 148).
· Suck reflex.
· Snout reflex (see p. 148).
· Orbicularis oculi reflex or glabellar reflex (see p. 137).
· Palpebral-oculogyric reflex.
· Orbicularis offs reflex.
Mention a few examples of facial synkinesis.
Facial synkinesis means that attempts to move one group of facial muscles result in contraction of associated muscles. It may be
seen during anomalous regeneration of the facial nerve. For example:
· If fibres originally connected with muscles of the face later innervate the lacrimal gland, anomalous secretion of tears (crocodile
tears) may occur while eating.
· If fibres originally connected with the orbicularis oculi innervate the orbicularis oris, closure of the eyelids causes retraction of
· Opening of the jaw may cause closure of the eyelids on the corresponding side (jaw-winking).
Have you heard of Mobius' syndrome?
Congenital facial diplegia, congenital oculofacial paralysis and infantile nuclear aplasia. It consists of congenital bilateral facial palsy
associated with third and sixth nerve palsies.
What is the relationship between diabetes and Bell's palsy?
Diabetes is said to be an important cause in about 10% of cases of Bell's palsy. In one study Bell's palsy was associated with
abnormal glucose tolerance in two thirds of patients (Lancet 1971; i: 108; Arch Otolaryngol 1974; 99: 114).
Sir Charles Bell (1774-1842) was Professor of Surgery in Edinburgh and a founder member of the Middlesex Hospital in London. He
discovered that the anterior and posterior spinal nerve roots were motor and sensory respectively.
James Ramsay Hunt (1874-1937), Professor of Neurology in New York.
RJ. Mbbius (1853-1907), a German neurologist.