A site for medical students - Practical,Theory,Osce Notes

Course of Facial nerve the 7 th cranial nerve

Important areas related to the course of facial nerve are the following.

  1. Pons.
  2. Cerebellopontine(CP)angle.
  3. Internal auditory meatus.
  4. Ear.
  5. Stylomastoid foramen.

Nucleus of facial nerve is situated in pons.
Nervus intermedius that carry sensory and parasympathetic fibers curve around the abducent(6) nucleus in the pons to form the facial colliculus.

CP angle
Facial nerve emerge at the ponto medullary junction and lies in the cp angle.

Internal auditory meatus
Facial nerve enters the internal auditory meatus with 8 th cranial nerve with the nervus intermedius inbetween.

This part is called labyrinthine part, and is situated above the labyrinth.This curves posteriorly at the genu, and gives the greature superficial petrosal nerve at the genu.
Then the nerve travel backward in the horizontal or tympanic segment above the middle ear.
Then it turns vertically in the vertical or mastoid segment.
In the vertical part facial nerve give two branch nerve to stapedius and chordatympani.

Stylomastoid foramen
Facial nerve emerge at the stylomastoid foramen.
Distal to the stylomastoid foramen,it gives 2 branches.
1.Posterior auricular nerve.
2.Branch to Posterior belly of Digastric muscle and Stylohyoid muscle.
Then it enters the parotid gland.
It leaves the parotid gland by dividing into temperofacial and cervicofacial branches.
Finally divides into five motor branches.
Five major branches of facial nerve  (in parotid gland) - from top to bottom are
a) Temporal branch.
b) Zygomatic branch.
c) Buccal branch.
d) Marginal mandibular branch.
e) Cervical branch.