CRANIAL NERVE VII

FACIAL NERVE(Nerve of second pharyngeal arch)

FUNCTIONS:

1. Special sensory (Taste)

2. General (somatic) sensory

3. Somatic (branchial) motor

4. Visceral (parasympathetic motor)

ORIGIN: From junction of pons and medulla As two divisions:

1. Motor root: innervates muscle of facial expression

2. Intermediate root: carries taste, parasympathetic and somatic sensory fibers

NUCLEUS:

1. Branchiomotor nucleus

2. Superior salivatory nucleus (Parasympathetic)

3. Lacrimatory nucleus (Parasympathetic)

4. Nucleus of Tractus Solitarius (Sensory)

COURSE: It crosses the posterior cranial fossa and leaves the

cranial cavity through the internal acoustic meatus then enters the facial canal in in petrous part of temporal bone. Near this point there is sharp bend called GENICULUM OF FACIAL NERVE site of geniculate ganglion. Finally it exists through stylomastoid foramen and give its branches.

BRANCHES: Within facial canal it gives:

1. Greater petrosal nerve

2. Nerve to stapedius

3. Chorda tympani nerve

From stylomastoid foramen it gives:

4. Digastric nerve

5. Posterior auricular nerve

6. Stylohyoid nerve

At Face:

7. Temporal Nerve

8. Zygomatic nerve

9. Buccal nerve

10. Mandibular nerve

11. Cervical nerve

SOMATIC MOTOR:Supplies muscle of facial expression and auricular muscles. Also supplies posterior bellies of digastric, stylohyoid and stapedius muscle.

VISCERAL MOTOR:

Provides parasympathetic fibers to pterygopalatine ganglion for innervation of lacrimal glands and to submandibular ganglion for innervation of submandibular and sublingual glands.

SOMATIC SENSORY:

Supply skin of concha of auricle

SPECIAL SENSORY:

Fibers carried by chorda tympani join the lingual nerve to carry taste sensation from anterior two thirds of tongue and soft palate

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