Facial Nerve

Facial nerve provides innervation to structures derived from

Striated muscles of facial expression is supplied by

Stapedius muscle is supplied by

Stylohyoid muscle is supplied by

Posterior belly of digastric muscle

Form the nervus intermedius

Lacrimal gland and seromucinius glands of nasal cavity is innervated by

Submanibular and sublingual glands is innervated by

Innervate the anterior 2/3 of the tongue via chorda tympani and tonsillar fossae and palate

Contains the cell bodies of sensory neurons

Provide sensation to touch of the external auditory canal amd co chal skin of the auricle

Provide proprioceptive info from the facial muscles

Supply mucisa of the nose, pharymx, and palate

Bony canal where FN traverse the temporal bone

Begins at the fundus of the internal auditory canal and terminates at the stylomastoid foramen

Frontal branch component of the facial nucleus

Accompanied by CN VIII, travels thru internal auditory canal to fundus

Narrowest point in the bony fallopian canal

Site where the nerve is most likely to become entrapped due to inflammatory swelling

Segment after runnjng a short distance anteriorly in which the facial nerve gives off the greatest petrosal nerve

Runs horizontally through the middle ear, passing above the stapes, to the aditus ad antrun near lateral semicircular canal

Course through the mastoid and leaves its biny canal at the stylomastoid foramen

Gives off chorda tympani, which contains the sensory gustatory fibers

Part after emerging the stylomastoid foramen

Enters the aprotid gland where it branches into the pes anserinus

Branches into the frontal, ophthalmic and oral branches which supllies the muscles for facial expression

Neuropraxia

Reversible conduction block

Axonotmesis

Loss of structural continuity of axon with intact endoneurial sheath

Neurotmesis

Loss of continuity of acons and endoneurial sheaths

Complete loss of nerve continuity

Loss of continuity of axons, sheaths, funiculus

Histologic and biohemical changes occur on the nerve cell when a nerve is injured by any means, trauma or systemic changes

Interruption of the continuity if the axon separates distal axo from metabolic source

Normal facial function in all areas

Mild Dysfunction

Gross: light weakness noticeable on close inspection, may have very slight synkenesis

Motion: complete closure of the eyes with minimum effort, mouth with slight asymmetry

Moderate Dysfunction

Gross: obvious but no disfiguring difference between 2 sides, noticeable but no severe synkinesis, contracture or hemifacial spasm

Motion: slight to moderate movement of forehead, complete closure of eyes with effort, mouth slightly weak with max effort

Gross: obvious weakness or disfiguring asymmetry

Motion: no in forehead, incomplete closure of eyes, mouth asymmetric with max effort

Gross: only barely perceptivle motion

Motion: no in forehead, incomplete closure of eyes, mouth with slight movement

No movement

Test in which the physician places a folded strip of sterile filter paper into the conjunctival fornix of each eye and compares rate of tear production of 2 sides