Detailed view of important facial & trigeminal nerves.....

1. Guided by:
Dr. adarsh desai
Dr. ravi kalola
Prepared by:
Aswathi Krishna [31]

2. FACIAL NERVE
 It is the 7th cranial nerve.
 It is the nerve of the 2nd branchial arch.

3. COURSE AND RELATIONS
 The facial nerve is attached to the brainstem by two
roots, motor and sensory.
 The sensory root is also called the nervus intermedius.
 The two roots of the facial nerve are attached to the
lateral part of the lower border of the pons just medial
to the eight cranial nerve.
 The two roots run laterally and forwards, with the 8th
nerve to reach the internal acoustic meatus.

4.  In the meatus, the motor root lies in a groove on the
eight nerve, with the sensory root intervening.
 Here the seventh and eighth nerves are accompanied
by the labyrinthine vessels.
 At the bottom or fundus of the meatus, the two roots,
sensory and motor, fuse to form a single trunk, which
lies in the petrous temporal bone.

5. .Within the canal the course of the nerve can be
divided into three parts by two bends.
.The 1st part is directed laterally above the vestibule .
.THE 2nd part runs backwards in relation to the
medial wall of the middle ear.
The third part is directed vertically downwards behind
the promontory.

7.  The first bend at junction of the first and second
part is sharp.
 It lies over the anterosuperior part of the promontory ,
and is also called genu.
 The geniculate ganglion of the nerve is called because
it lies on the genu.
 The second bend is gradual and lies between the
promontory and the aditus to the mastoid antrum.

8. Branches and distribution
 A. Within the facial canal
1.greater petrosal nerve
2.The nerve to the stapedius
3.The chorda tympani
 B. At its exit from the stylomastoid foramen .
 1. Posterior auricular
 2. Digastric
 3. stylomastoid
 C. Terminal branches within the partoid gland
 1. Temporal
 2. Zygomatic
 3. Buccal
 4. Marginal mandibular
 5. Cervical
 D. COMMUNICATING BRANCHES WITH ADJACENT CRANIAL AND SPINAL
NERVE

10.  1.The nerve to the stapedius
 It arises opposite the pyramid of middle ear.
 It supplies stapedius muscle.
 Paralysis of this muscle cause hyperacusis.
 2. CHORDA TYMPANI
 Arises in vertical part of facial canal.,about 6mm above the
stylomastoid foramen.
 It enters from middle ear and runs forward in close relation to
the tympanic membrane .
 It leaves middle ear by passing through petrotympanic fissure.
 In infratemporal fossa it joins lingual nerve.

11.  3. POSTERIOR AURICULAR NERVE
 Arises just below the stylomastoid foramen.
 It ascends between mastoid process and external
acoustic meatus.
 It supplies :
1. Auricularis posterior
2. 0ccipitalis
3. Intrinsic muscle on the back of
auricle.

12.  4.DIGASTRIC BRANCH
 Supplies the posterior belly of the digastric.
 5. STYLOHYOID BRANCH
 Arises with the digastric branch
 Supplies the stylohyoid muscle.

13.  6. TEMPORAL BRANCHES
 Supplies : 1. auricularis anterior
 2. auricularis posterior
 3. intrinsic muscles on the lateral
 side of the ear
 4.frontalis
 5. orbicularis oculi
 6. corrugator supercilli

14.  ZYGOMATIC BRANCHES
 It runs across the zygomatic bone and supply the orbicularis oculi.
 BUCCAL BRANCHES : upper buccal branch
 lower buccal branch
 upper branch runs above parotid duct.
 lower branch runs below parotid duct.
 THE MARGINAL MANDIBULAR BRANCH
 Runs below the angle of mandible deep to platysma.
 It supplies muscle of lower lip and chin.


15.  CERVICAL BRANCH
 Emerges from the apex of parotid gland
 Runs downwards and forwards in neck to supply
platysma.

16.  The ganglia associated with facial nerve are:
 1. The geniculate ganglion .
 2. The submandibular ganglion
 3. The pterygopalatine ganglion