Which of the following is NOT a lower motor neurone cause of a facial nerve palsy?

e. An upper motor neurone paralysis is usually seen as a result of a stroke. It results in weakness of the facial muscles but spares the muscles of the forehead due to their dual innervation. The facial nerve arises from its origin in the pons and travels past the cerebello-pontine angle through the petrous part of the temporal bone to emerge via the stylomastoid foramen into the parotid gland where it divides into branches. Along its course it traverses with the chorda tympani and the nerve to stapedius, therefore if there is a lesion in the petrous temporal bone the facial weakness is accompanied by hyperacusis and loss of taste on the affected side.

Bell’s Palsy is by far the commonest cause of a lower motor neurone lesion and is a diagnosis of exclusion. It is believed to result from a viral infection and results in swelling of the nerve in the petrous temporal bone. The absence of symptoms in any of the other cranial nerves helps to secure the diagnosis. Management involves time and most patients make a full and spontaneous recover over a period of months.