For medical, nursing, and physiotherapy undergraduates, and postgraduates

1. FACIAL NERVE

2. INTRODUCTION
 It is the Seventh cranial nerve.
 Known as ‘Queen of Face’
 It’s the nerve of 2nd Branchial arch.
 It is a mixed nerve with two components / roots
:
1. Motor root
2. Sensory root / Nervus Intermedius / Nerve of
Wrisberg

3. STRUCTURE OF NERVE
• Inside out
o Axon
o Myelin sheath
o Neurilemma
o Endoneurium
o Perineurium to form Fascicle
o Epineurium

4. FUNCTIONAL COMPONENTS
1. Branchio-motor fibres :
2. Pre-ganglionic Secreto-motor fibres :
3. Taste fibres :
4. Cutaneous Somato-sensory fibres :

5. FUNCTIONAL COMPONENTS
1. Supply muscles from 2nd Branchial arch.
1. For Submandibular, Sublingual, lacrimal
glands, glands of Soft palate and Nasal cavity.
2. Taste fibres from Anterior 2/3rd of tongue and
from soft palate.
3. Cutaneous Somato-sensory fibres from the
concha of the auricle.

7. DEEP / NUCLEAR ORIGIN
1. Motor nucleus :
• It is situated in caudal part of pons and in
front of Abducent nucleus.
• It represents Special Visceral (Branchial)
Efferent column / Branchio-motor :
• Three nuclear sub-groups are :
i. Lateral
ii. Intermediate
iii. Medial

8. DEEP / NUCLEAR ORIGIN
i. Lateral group :
• Buccal musculature and Buccinator
ii. Intermediate group :
• Orbicularis oculi, muscles of forehead and
upper face.
iii. Medial group :
• Dorso-medial set – auricular muscles,occipito
frontalis ms.
• Ventro-medial set – Platysma.

9. MOTOR ROOT FIBRES
• The fibres from Motor nucleus pass Dorso-medially,
towards caudal end of Abducent nucleus.
• Then they pass rostrally superficial to it forming
Facial colliculus.
• At the cranial end of Abducent nucleus,the fibres
bend abruptly downwards and forwards forming an
Internal Genu.
• Finally emerge at the Lower border of the Pons
through the Motor root.

11. DEEP / NUCLEAR ORIGIN
2. Superior Salivatory nucleus : located Dorso-
lateral to the caudal part of the motor
nucleus and represents General Visceral
Efferent column.
• It gives origin to the Pre-ganglionic secreto-
motor (parasympathetic) fibres which emerge
out through the sensory root hence it’s a
misnomer.

13. DEEP / NUCLEAR ORIGIN
3. Upper part of nucleus of Tractus Solitarius :
represents Special Visceral Afferent column.
• The cell bodies of these fibres lie in Geniculate
ganglion.
• It receives taste sensations from :
• Anterior 2/3rd of tongue via Chorda tympani
nerve except Vallate papilla &
• Soft palate via Greater Petrosal nerve.

14. DEEP / NUCLEAR ORIGIN
4. Upper part of Spinal nucleus of Trigeminal
nerve : represent General Somatic Afferent
column.
• The cell bodies of these fibres lie in Geniculate
ganglion.
 It receives cutaneous sensations from :
• Auricle via Auricular branch of Vagus nerve.

15. CENTRAL CONNECTIONS
 The Cortico-nuclear fibres of opposite side
control activities of motor nucleus which
supplies muscles of Lower part of face.
 Motor nucleus supplying muscles of upper
part of face (forehead & eyelids) is controlled
by Cortico-nuclear fibres of both sides.

16. SUPERFICIAL ORIGIN
 The Facial nerve arises from two roots on the
ventral aspect of brainstem from lower border
of pons between the Olive and Inferior
Cerebellar peduncle.
1. Motor root – large, lies medially.
2. Sensory root / Nervus Intermedius – smaller,
lies laterally and sometimes
• Vestibulo-cochlear nerve – lateral to sensory
root.

19. COURSE AND RELATIONS
 The course is divided by Internal Acoustic
meatus and Stylomastoid foramen into :
1. Intra-cranial : 23-24 mm
2. Intra-temporal part : 28-30 mm
3. Extra-cranial part :

20. INTRA-CRANIAL PART
 From the Brainstem
 Enter Internal Accoustic meatus
 At the bottom of the meatus :

22. INTRA-TEMPORAL PART
 In Bony canal, the nerve passes laterally, above
the vestibule of internal ear.
 After reaching medial wall, it bends backwards
forms a Genu (External).
 At the genu, asymmetrical swelling called
Geniculate Ganglion.

23. INTRA-TEMPORAL PART
 From the Genu, it passes backwards and
downwards in bony canal, above promontory
to reach the medial wall of aditus to Mastoid
antrum.
 Finally, the nerve passes vertically downwards
along posterior wall of tympanic cavity and
exits temporal bone through Stylomastoid
foramen.

27. EXTRA-CRANIAL PART
 After exit from Stylomastoid foramen, it
passes forwards and laterally, superficial to
Styloid process.
 It pierces postero-medial surface of parotid
gland.
 Within gland it lies –
 It divides into : Temporo-facial & Cervico-facial
trunks.
 Finally -

28. BRANCHES

35. PECULARITIES
 The facial nerve presents Two genu :
1. Internal genu
2. External genu
 In the entire extent, it changes direction five
times :

36. BRANCHES OF COMMUNICATION
 In Internal Acoustic meatus : With Vestibulo-
cochlear nerve.
 At Geniculate ganglion :
1. With Pterygo-palatine ganglion through Greater
Petrosal nerve.
2. With Otic ganglion through a branch with joins
with Lesser Petrosal nerve.

37. BRANCHES OF COMMUNICATION
3 With Sympathetic plexus around Middle
Meningeal artery – through a branch known as
External Petrosal nerve.
 In the Facial canal :
1. With Auricular branch of Vagus nerve.
 Below the Stylomastoid foramen :
1. With IX, X, Auriculo-temporal & Great auricular
nerves.

38. BRANCHES OF COMMUNICATION
 Behind the ear :
1. With Lesser Occipital nerve.
 In the face :
1. With branches of Trigeminal nerve.
 In the neck :
1. With Transverse Cervical Cutaneous nerve.

39. BRANCHES OF DISTRIBUTION
 In the Facial canal : (Two)
1. Nerve to Stapedius :
2. Chorda-tympani nerve :
 Below Stylomastoid foramen :
1. Posterior auricular nerve :
2. Nerve to Posterior belly of Digastric :
3. Nerve to Stylohyoid muscle :

40. BRANCHES OF DISTRIBUTION
 In the Face : (Five terminal branches)
1. Temporal
2. Zygomatic
3. Buccal
4. Marginal mandibular
5. Cervical

41. FIVE TERMINAL BRANCHES
1. Temporal branch :
• Intrinsic ms of lateral & superior surface of
auricle
• Auricularis anterior & superior
• Upper part of Orbicularis oculi
• Frontalis and corrugtor supercilli.
2. Zygomatic branch : Lower part of Orbicularis
oculi

42. FIVE TERMINAL BRANCHES
3 Buccal branch :
• Superficial – Procerus
• Deep :
• Upper – Z Major, Z Minor, Levator Anguli Oris,
Levator Labii Superioris, LLSAN, Muscles of Nose.
• Lower – Buccinator, Orbicularis Oris.
2. Marginal Mandibular branch : Risorius, Depressor
Anguli Oris, Depressor Labii Inferioris & Mentalis.
2. Cervical branch – Platysma.

43. APPLIED ANATOMY
 Stylomastoid foramen -
 Lesions of Facial nerve – 3 types
1. Supra nuclear paralysis : involves Upper motor
neurons
2. Nuclear paralysis : involves lower motor neurons
3. Infra nuclear paralysis : involves lower motor
neurons

44. APPLIED ANATOMY
 Bells palsy :
 It’s a flaccid type of lower motor neuron
paralysis.
 It may be caused by sudden exposure to cold,
middle ear infections, fractures, tumours etc.
 75 % of all facial nerve lesions are Bell’s palsy.

45. APPLIED ANATOMY
1. In Acoustic meatus : Bells palsy with
deafness.
2. Lesion at Genu : Diminishes lacrimation,
submandibular salivary secretion, reduced
taste sensation, hyperacusis along with Bell’s
palsy.
3. Lesion between Genu and Pyramidal
eminence : all manifestations as in 2, except
disturbance of lacrimation & taste sensation.

46. APPLIED ANATOMY
4. Injury to Facial nerve below Stylomastoid
foramen : produces Bells palsy without
affecting other functions.
• Transverse wrinkles on forehead disappear
and eye brow droops.
• Palpebral fissure wider d/t unopposed action
of LPS.
• Nasolabial fold disappears, tip of nose
deviated to normal side.

47. APPLIED ANATOMY
• Paralysis of Buccinator – food acumulates in
vestibule of mouth and dribbles out
occasionally.
• Lips on affected side can’t move hence
pursing of whistle is disturbed and also labial
speech.
• During smiling, angle of mouth remains
motionless on affected side, whereas other
angle moves up and laterally, making oral
fissure triangular in outline.