FACIAL NERVE ANATOMY - PRECISE

1. FACIAL NERVE ANATOMY
- Nithin nair

2. INTROduCTION
• Seventh cranial nerve.
• Nerve of the second branchial arch.
• Mixed cranial nerve with sensory and motor
components.
• Sensory root (nervus intermedius)
• Motor root (nerve of wrisberg)

3. FuNCTIONAL COMpONENTs
Funcional
components
Nucleus and its location Functions
Special visceral
efferent
Motor nucleus at lower part of
pons
•Muscle of facial expression
•Elevation of hyoid bone
General visceral
efferent
•Superior salivatory nucleus at
lower part of pons.
•Lacrimatory nucleus overlapped
by sup. salivatory nucleus
•Secretomotor to
a) Submandibular
b) Sublingual salivary glands.
c)Lacrimal gland
d)Glands of nose, palate, pharynx
Special visceral
afferent
Nucleus of tractus solitarius at
junction of pons and medulla.
•Taste sensation from anterior
2/3rd
of tongue except from vallate
papillae and palate.
General somatic
afferent
Sensory nucleus at rostral end of
nucleus solitarius
•General sensation from skin of
concha of external ear
•Proprioceptive sensation from
muscle s supplied by nerve.

6. COuRsE ANd RELATIONs
• The facial nerve is attached to the brainstem by
two roots-motor & sensory.
• The two roots of the facial nerve are attached to the
lateral part of the lower border of the pons just
medial to eighth cranial nerve.
• The two roots run laterally & forwards,with eighth
nerve to reach internal accoustic meatus

7. Course and relations…
• In the meatus,the motor root lies in a
groove on the eighth nerve.
• Here seventh & eighth nerves are
accompanied by the labyrinthine vessels.
• At the bottom or fundus of the meatus, the
two roots sensory & motor fuse to form a
single trunk,which lies in the petrous
temporal bone.
• Within the canal, the course can be divided
into three parts by two bends.

8. Course and relations…
• The first part is directed laterally above the
vestibule.
• The second part runs backward in relation to
the medial wall of the middle ear,above the
promontory.
• The third part is directed vertically downwards
behind the promontory
• The first bend at the junction of the first &
second part is sharp.
• It lies over the anterosuperior part of the
promontor,& is also called the genu.

9. Course and relations…
• The second bend is gradual & lies between
promontory & aditus to the mastoid antrum.
• The facial nerve leaves the skull through the
stylomastoid foramen.
• In the extra cranial course,the facial nerve
crosses the lateral side of the base of the
parotid gland crossing the retromandibular
vein & external carotid artery.
• Behind the neck of mandible it divides into its
five terminal branches which emerge along the
anterior border of the parotid gland.

10. Branches and distriBution
1. WITHIN THE FACIAL CANAL :
• Greater petrosal neve
• The nerve to the stapedius &
• The chorda tympani
2. AT ITS EXIT FROM STYLOMASTOID FORAMEN
• Posterior auricular
• Diagastric
• Stylohyoid

11. Branches and distribution…
3. TERMINAL BRANCHES
• Temporal
• Zygomatic
• Buccal
• Marginal mandibular
• Cervical
4. Communicating branches with adjacent cranial
& spinal nerves.

12. MuscLes suPPLied
• The nerve to the stapedius arises opposite
pyramid of middle ear and supplies stapedius
muscle
staPedius MuscLe
• The stapedius lies in a bony canal that is related to
the posterior wall of the middle ear.
• It carries:Preganglionic secretomotor fibres to the
submandibular salivary ganglion for supply of
submandibular & sublingual salivary glands &
taste fibres from the anterior two-thirds of the
tongue.

13. MUSCLE SUPPLIED…
• Posterior auricular nerve supplies :
1. Auricularis posterior.
2. Occipitalis
3. Intrinsic muscle on the back of the auricle.
Muscle Origin Insertion Action
Auricularis
posterior
Galeal
aponeurosis
Front of helix,cranial
surface of middle ear
Underdeveloped
in human
(wiggle of ears)
Occipitalis Two occipital
bellies & two
frontal bellies
galeal aponeurosis Raises eyebrow,
wrinkles forehead.

14. Auricularis posterior
Occipitalis

15. MUSCLE SUPPLIED…
• Diagasric branch supplies posterior belly of
digastric.
Muscle Origin insertion Nerve
supply
Action
Posterior
belly of
digasric
Mastoid
notch of
temporal
bone
Thyroid
bone.
Facial nerve • Depresses
mandible when
mouth is widely
opened or
against
resistance
• Elevates hyoid
bone.
digasric

16. MUSCLE SUPPLIED…
• Stylohyoid branch supplies stylohyoid muscle.
Muscle Origin Insertion Nerve
Supply
Action
stylohyoid
muscle.
Posterior
surface of
styloid
process
Junction of
body &
greater
cornua of
hyoid bone
Facial nerve •Pulls hyoid
bone upwards
& backwards
•It fixes the
hyoid bone.
stylohyoid
muscle.

17. MUSCLE SUPPLIED…
• Temporal branches supply:
1. Auricularis anterior
2. Auricularis superior
3. Intrinsic muscle on the lateral side of ear.
4. Frontalis
5. Orbicularis oculi
6. Corrugator supercilii

18. MUSCLE SUPPLIED…
Muscle Origin Insertion Nerve
supply
Action
Auricularis
anterior and
auricularis
superior
Galeal
aponeurosis
Front of
helix,cranial
surface of
middle ear
Facial nerve Undeveloped in
humans
Frontalis Galeal
aponeurosis
skin of
eyebrows and
nose
Facial nerve Raises eyebrows
and wrinkles
forehead
Orbicularis
oculi
•Medial and
lateral part of
medial
palpebral
ligament.
•Lacrimal fascia
and bone
Upper and
lower eyelids
Facial nerve Closes lids
tightly,wrinkling,pro
tects eye from
bright light,blinking.
Corrugator
supercilii
Medial end of
superciliary
arch.
Skin of mid eye
brow
Facial nerve Frowning

19. Orbicularis oculi
Corrugator supercilii
Frontalis
auricularis
superior
Auricularis anterior

20. MUSCLE SUPPLIED…
• Zygomatic branches supply orbicularis oculi.
• The buccal branches are two in number.The upper buccal
branch runs above the parotid gland & the lower buccal
branch below the duct.
• Upper buccal branch supplies:
1) Zygomatic major and minor
2) Levator labii superioris
3) Levator anguli oris
4) Nasalis
• Lower buccal branch supplies:
1) Buccinator
2) Orbicularis oris

22. MUSCLE SUPPLIED…
• The marginal mandibular branch runs below the
angle of mouth deep to platysma and supplies
risorius muscle.
Muscle Origin Insertion Nerve
supply
Action
Risorius Fascia over
masseter
Skin over
angle of
mouth
Facial nerve Draws angle
of mouth
laterally

23. MUSCLE SUPPLIED…
• The cervical branch emerge from apex of the
parotid gland & supply to the platysma.
Muscle Origin Insertion Nerve supply Action
Platysma Pectoralis and
deltoid fascia.
Lower border
of mandible
Facial nerve Depresses
mandible and
draws angle of
the mouth
downward.

24. MUSCLE SUPPLIED…
• Communicating branches: for coordination
between the movements of the muscles of the first,
second and third branchial arches. The motor
nerves of the three arches communicate with each
other.

25. Reference……
• Human Anatomy( B D Chaurasia) Vol:3
• Google
• Anatomy ( Shoukat N. Kazi)
• www.scribd.com