D. Systemic lupus erythematosus – Explanation
Facial nerve
Supply – ‘face, ear, taste, tear’
- face: muscles of facial expression
- ear: nerve to stapedius
- taste: supplies anterior two-thirds of tongue
- tear: parasympathetic fibres to lacrimal glands, also salivary glands
Causes of bilateral facial nerve palsy
- sarcoidosis
- Guillain-Barre syndrome
- polio, Lyme disease
Causes of unilateral facial nerve palsy – as above plus
Lower motor neuron
|
Upper motor neuron
|
LMN vs. UMN
- upper motor neuron lesion ‘spares’ upper face i.e. forehead
- lower motor neuron lesion affects all facial muscles
*may also cause an UMN palsy
