CN7 Facial nerve Flashcards
What is cranial nerve 7?
Facial nerve
What is the route of the CN7 facial nerve?
Runs through internal auditory meatus in petrous part of temporal bone gives off intracranial branches here leaves through the stylomastoid foramen runs to the parotid gland divides into extracranial branches
How many extracranial branches of the CN7 facial nerve are there?
Five
What are the five extracranial branches of the CN7 facial nerve?
Temporal branch
Zygomatic branch
Buccal branch
Mandibular branch
Cervical branch
How are the five extracranial branches of the CN7 facial nerve named?
According to where they are located in the head and neck
What are the functions of the CN7 facial nerve?
Special sensory - taste from anterior two thirds of tongue
Motor - muscles of facial expression
Autonomic parasympathetic - lacrimal gland, submandibular and sublingual salivary glands
What do the five extracranial branches of the CN7 facial nerve innervate?
Muscles of facial expression
What do the intracranial branches of the CN7 facial nerve innervate?
Anterior two thirds of tongue
Lacrimal glands
Submandibular and sublingual salivary glands
What can cause damage to the facial nerve?
Facial trauma
Disease or surgery of parotid gland
Bell’s palsy
What are the consequences of damage to the facial nerve?
Paralysis or weakness of muscles of facial expression
How are the functions of the CN7 facial nerve tested?
Motor - test muscles of facial expression
corneal reflex
Special sensory - taste of anterior two thirds of tongue
What happens in Bell’s palsy?
Inflammation of facial nerve
oedema results in compression of the nerve when it is in the petrous bone
A facial nerve palsy with ipsilateral parotid gland enlargement is likely to be what? It is unlikely to be what?
Likely to be parotid cancer
Unlikely to be benign, infective or inflammatory cause to do with parotid gland
