Facial nerve palsy
Mild left facial nerve palsy. Note the
slightly drooping of the corner of the
Getting the patient to smile reveals
asymmetry of the action of the facial
Getting the patient to forcibly shut her
eyes. The left lashes are not buried due
to the decreased tone of orbicularis oculi.
The most common type of facial nerve palsy seen is unilateral lower facial nerve palsy. Supranuclear facial nerve is
uncommon in ophthalmology examination because the eyes are not involved. Remember not to use the term Bell's palsy
as synonymous with lower facial nerve palsy; Bell's palsy is a diagnosis of exclusion when other known causes of lower
facial nerve palsy has been considered.
The patient has loss of nasolabial fold and the forehead wrinkles of the affected side (in severe cases, there may be dropping
of the corner of the mouth and obvious ectropion). The eyebrow of the affected side is lower (brow droop) and the upper lid
is retracted (ie. a wider palpebral aperture due to the unopposed action of the levator). The blink rate on the affected side is
reduced. There is impaired blowing of the cheek, and asymmetrical movement of the corner of the lip on smiling. On eyelid
closure, the affected side could not close the eye lid fully (or it can be easily opened).
Further examination for any signs of aberrant regeneration suggesting the lesion is long-standing, the following signs are
- Check for Bell's phenomenon, by observing if the eyes move up on attempted lid closure (you may need to keep the
eyelids open to observe this but avoid hurting the patient)
- Test the cornea sensation.
the most common:
- Look for twitching of the mouth when the patient blink
- Look for closure of the eye or asymmetrical narrowing of the palpebral fissure on smiling
- Any signs of vesicles on the external ear ? (Ramsey-Hunt's Syndrome)
- Any signs of parotid swelling or scar over the parotid gland? (sarcoidosis, parotid gland tumour or recent parotid
- Any signs of deafness? (previous mastoid abscess)
- Any loss of cornea and facial sensation? (cerebellopontine lesion)
- Any scar behind the ear or behind the neck? (previous mastoid operation or acoustic neuroma operation)
- In patient with contralateral hemiplegia, test the eye movement for ipsilateral gaze palsy and loss of facial sensation
from fifth nerve involvement (Foville's Syndrome).
1. How can you determine the level of lower facial nerve palsy?