This document provides information on the surgical anatomy of the facial nerve. It begins with an introduction to the facial nerve and its functional components and nuclei. It then describes the different parts of the facial nerve from its intracranial portion to its extra-temporal portion in the neck. Several clinical considerations are discussed, including Bell's palsy, Ramsay Hunt syndrome, and Guillain-Barre syndrome. Surgical techniques for facial nerve repair are outlined, including nerve grafting and substitution techniques like hypoglossal-facial nerve crossover. In summary, this document details the anatomy and clinical implications of the facial nerve as well as surgical strategies for repairing injuries to this nerve.

2. SURGICAL ANATOMY OF FACIAL NERVE
STRUGGLE IS IN THE DETAILS-UNKNOWN
PRESENTED BY- DR.AMAR SHINDE GUIDED BY- DR.SHREYAS GUPTE

3. INTRODUCTION
• Seventh cranial nerve
• Nerve of the second branchial arch
• The facial nerve consists of the facial nerve proper and the
intermedius nerve.
• Composed of fascicles that increase in number along its course in the
temporal bone.
3

4. Functional Components OfFacial Nerve
1. Special Visceral Efferent(SVE)- responsible for facial expression
2. General Visceral Efferent(GVE)- Secretomotor to Submandibular and Sublingual
Salivary Gland, the Lacrimal gland, gland of nose, palate and pharynx
3. Special Visceral Afferent(SVA)- carry taste Sensation
4. General Somatic Afferent(GSA)- innervates part of skin of ear

6. Nuclei of Facial Nerve
• Motor Nucleus
• Superior Salivatory Nucleus (PARASYMPHATIC)
• Nucleus of TractusSolitarius (GUSTATORY)
• LACRIMATOUS NUCLEUS (PARASYMPHATIC)

8. Parts of facialnerve
Intracranial part: from pons to Internal auditory canal(IAC) 24mm
Intra-temporal part: from IAC to stylomastoid foramen 28-30mm
 Meatal segment (8mm) from the entracne of IAC to fundus
 Labyrinthine segment(3-5mm) from the fundus to geniculate
ganglia
 Tympanic segment (11mm)from geniculate ganglia to 2ndgenu
Mastoid segment (13mm) from 2ndgenu to stylomastoid foramen Extra-
temporal part(Neck and parotid gland part
From stylomastoid foramen to termination of its peripheral branches

10. NERVE TO STAPEDUS SUPPIES STAPEDIUS MUSCLE
THE FUCTION OF STAPEDUS MUSCLE IS TO DAMP EXCESSIVE VIBRATION CAUSED BY HIGH PITCH SOUND
IN PARALYSIS OF THIS MUSCLE EVEN NORMAL SOUND APPERS TO LOUD AND THIS IS KNOWN AS
“HYPERACUSIS”

11. POINT TO PONDER
FACIAL RECESS IS A ROUTE TO MID EAR CAVITY TO PERFORM
COCHLEAR IMPLANTATION
2 THINGS ABOUT FR
TWO MAJOR BOUNDARIES
1.FACIAL NERVE
2.CHORDA TYMPANI
TWO IMP COMPLICATIONS
1. FACIAL PARALYSIS
2. TASTE DISORDER

13. • The main trunk of the facial nerve divides into five major division in
Parotid Gland-
– Temporal
– Zygomatic
– Buccal
– Marginal Mandibular
– Cervical

15. Temporalbranch
• Emergefrom theparotid gland at its upper pole
slightly in front of the superficial temporal artery
• Anterior temporal : frontalis, superior part of
orbicularisoculi, corrugator supercilii, procerus
• Posterior temporal : anterior andsuperior
auricular muscles

16. Zygomaticbranch
• Leave the parotid gland on its
anterosuperior border
• Crosses the body of Zygomatic
bone
• Supply part of orbicularis
oculi

17. Buccalbranch
• Emergeat the anterior border of parotid
• Upper Buccal: muscles of upper lip and themuscles of the nose
• Lower Buccal : Buccinator and Risorius
• Orbicularis Oris
• It run parallel and 1 cm below the Zygomaticarch and often along
inferior aspect of parotid duct

18. Marginalmandibular
• Runs parallel to lower border of themandible
• Cross Facialvein and Facialartery
• Supplies muscles oflower lip (Depressoranguli oris
and Depressorlabii inferioris) and mental muscles
• Located 1-2 cm belowthe inferior ramus of mandible

19. Cervical
Supplies Platysma

20. Clinical anatomy
• Supranuclear and Infranuclear lesions.
• In Supranuclear lesions; usually a part of hemiplegia, only lower part of the opposite side of
the face is paralyzed. The upper part with the frontalis and orbicularis oculi escapes due to
bilateral representation in the cerebral cortex
• In Infranuclear lesions, known as Bell’s palsy,the whole of the face of the same side gets
paralyzed. The affected side is motionless. Wrinkles disappear from the forehead. Eye
cannot be closed. Food accumulates b/w cheek and teeth duringmastication.

23. 1. Idiopathic: Bell’s palsy
MelkerssonRosenthal syndrome
2. Temporalbone trauma: Road trafficaccident
3. Infection: C.S.O.M.,Herpes Zoster oticus
Malignantotitis externa
4. Neoplasm: Parotid tumors, Acoustic Neuroma,
Glomus tumors, Malignancy ofear
5. Congenital: Moebiussyndrome
6. Iatrogenic: Mastoidectomy,Parotidsurgery
7. Metabolic: Diabetes mellitus,Hypertension
Etiologyof FacialNerve Palsy

25. • Symptomsaccordingtothe levelof injuryof facialnerve-
– Atinternalauditory meatus; loss of lacrimation, stapedialreflex, taste from most of anterior two-third
of tongue, lack of salivation and paralysis of muscles of facial expression
– Below geniculate ganglion; loss of stapedial reflex, taste from anterior two-third of tongue, lack of
salivation and paralysis of facial expression muscles
– Region b/w nerve to Stapedius and chorda tympani : loss of taste from anterior two-third of tongue,
lack of salivation and paralysis of facial expression muscles.
– Region below stylomastoid foramen : paralysisof facial expression muscles.

26. Applied aspect of facial nerve
facial nerve palsy in newborn
the mastoid process is absent in newborn and stylomastoid foremen is superficial .
Manuplation of baby head during delivery may cause damage to facial nerve. this lead to paralysis of facial muscle
especially buccinator required for sucking

27. Crocodile tears syndrome
lacrimation during eating occurs due to aberrant regeneration after trauma
in this case damage of facial nerve proximal to geniculate ganglion regenerates fiber for submandibular salivary
gland grow in endoneural sheath of preganglionic secretmotor fibers supplyng the lacrimal gland that why
patient lacrimate while eating

28. Ramsay hunt syndrome
geniculate ganglia by herpes zoster result in this syndrome
a] hyperacusis
b] loss of lacrimination
c] loss of sensation of taste in ant 2/3rd of tongue
d] bell palsy and lack of salivation
TREATMENT:
ANTIVIRALS AND STEROIDS.
TO BE TREATED WITHIN 3 DAYS OF
APPEARANCE OF SYMPTOMS.
THE CLASSICAL SYMPTOM THAT CLINICALLY DISHTINGUISHES RAMSAY HUNT SYNDROME IS A
RED PAINFUL RASH ASSOCIATED
WITH BLISTERS IN THE EARS AND ANTERIOR 2/3RD OF TONGUE . WITH FACIAL PARALYSIS ON
ONE SIDE OF FACE.

29. Bell’s palsy
BELL’S PALSY ( IDIOPATHIC FACIAL PARALYSIS) :
WAS FIRST DISCRIBED BY SIR CHARLES BELL.
BELLS PALSY IS CERTAINLY THE MOST COMMON CAUSE
OF FACIAL PARALYSIS WORLD WIDE.
CRITERIA :-
UNILATERAL
PERIPHERAL
ACUTE ONSET
NO APPARENT CAUSE
DOES NOT INVOLVE ANY OTHER FACIAL NERVE.

30. FEATURES OF BELL’S PALSY :
UNILATERAL INVOLVEMENT
UNABLE TO SMILE, RAISE EYEBROW, CLOSE EYES
DIFFICULTY IN WHISTLING
DROOPING OF THE CORNER OF MOUTH
UNABLE TO WRINKLE FOREHEAD
LOSS OF BLINKING REFLEX
SLURRED SPEECH
MASK LIKE APPEARANCE OF FACE
LOSS OR ALTERATION OF TASTE

31. MANAGEMENT OF BELL’S PALSY:
MEDICAL TREATMENT:
CORTICOSTEROIDS -PREDNISOLONE 1mg /kg/day 7-10 DAYS.
ANTIVIRAL DRUGS – ACYCLOVIR 400mg 5 times/day.
FLAMCOVIR & VALACYCLOVIR 500mg bid.
SURGICAL TREATMENT:
FACIAL NERVE DECOMPRESSION.
INDICATED WHEN THERE IS COMPLETE PARALYSIS.
PROGNOSIS :
PARIAL PARALYSIS ALWAYS RESOLVES COMPLETELY WITHIN A FEW WEEKS.
IN CASE OF COMPLETE PARALYSIS SEVERAL MONTHS ARE REQUIRED IN RECOVERY BUT IS ONLY POSSIBLE IN 60% TO
70% OF CASES
APPROXIMATELY 15% OF PATIENTS ARE LEFT WITH TROUBLESOME RESIDUAL PALSY OR AND SYNKINESIS.

32. FACIALNERVE MOTOR DYSFUNCTIONGRADINGSYSTEM :

33. Facial Nerve Grading System2.0

35. GUILLIAN BARRE SYNDROME :
HETEROGENEOUS GROUP OF
AUTOIMMUNE DISORDERS,
INVOLVING SENSORY, AUTONOMIC, MOTOR
NERVES AND IS THE MOST COMMON CAUSE OF
RAPIDLY PROGRESSIVE FLACCID PARALYSIS.
CAUSED BY CAMPYLOBACTOR JEJUNI
THE PATIENT IS CHARACTERIZED BY :
SYMMETRICAL ASCENDING MUSCLE PARESIS,
AREFLEXIA ALONG WITH A VARIABLE DEGREE OF
SENSORY OR AUTONOMIC DEVELOPMENT.

37. DIAGNOSTIC TEST

38. Nerve anatomy
epineurium – outer connective tissue layer of the nerve .supporting and protective connective tissue made up primarily of collegen and
elastic fibers.
Perineurium – act as diffusion barrier as a result of its selective permeability separating .this separation preserves the ionic
environment within fascicle
endoneurium – composed of gelatinous collegen matrix

39. Proximal segement of nerve
At the proximal level of injury the nerve attempt to regenerate
Each nerve fiber develops into regerating unit composed of many
small fibers
At tip of each fiber is growth cone with multiple filopodia.it is this
filopodia that samples the neural environment adhere to basal lamina
of schwann cell and advance the regerating unit in distal direction
Each axon send many growth cone which have protein GAP43 as a
componenet of cell membrane and each growth cone has motile
properties dependent on actin myosin interaction
The growth cone advance along the basement cell substrate of distal
segment corresponding BAND OF BUNGNER

40. DISTAL SEGMENT
Portion of nerve distal to transection undergoes Wallerian
degeneration
Schwann cell proliferate and take on a phagocytic role removing
axonal and myelin debris
Basal lamina of schwann cell provides chemotactic scaffolding for
the advancing growth cone.schwann cell are candidate for growth
factor

41. Surgical section
nerve repair

42. Facial nerve strategies intended to improve surgical outcomes
1. lesion is resected
2. branches to forehead and extra branches to midface and neck
clipped to discourage faulty regeneration and growth of axon to
unessential areas
3. sural cutaneous graft
4.nerve reversed so that distal end of graft is attached to proximal
end of donor nerve

43. Surgical principles of nerve repair
1. connect the defect between the proximal and distal end of nerve
without tension [ The bridge created by the graft should form “S” or
“C” ]
2. match the endoneurial surface of each other

44. Approximating the loose connective tissue of epineurium may achieve closure but the endoneurial suface tend to retract
and leave a gap that will eventually be filled by connective tissue blocking axon

45. Reexploration after 30 days or longer after intial repair one will encounter a beyond reactive neuroma at
proximal end and a fibrous stand collapsed and collagenized at distal end . If one waits beyond the ideal time
window [upto 30days and not beyond 6 month] one loses the opportunity for effective nerve repair

46. The proximal and distal end should be resected even if it
mean creating the larger gap since an interposition graft is
appropriate in either case

47. The graft should form an “S” and “C” in order to ensure adequate
length and repair without tension thus avoiding the problem
depicted

48. Few condition Based on 2nd principle of nerve graft

49. Epineural match and endoneural mismatch in this case once the epineurial
surface was stripped back it was clearly a poor endoneural surface match
that would not have been detected if the nerve ends were sutured together
without stripping back the epineurium

50. Epineural mismatch and endoneurial match

51. Endoneural match with histologic mismatch in this case xsectional diameter of nerve to b approximated
seem to match quite well even upon stripping back the epineurium the endonurial surface appears quite
adequate. nevertless there are times when endoneurial surface seems to be adequate but the actual axon
content is not in proportion to the endoneurial surface when the end of nerve is studied histologically

52. Nerve graft
length and axon volume are the most critical feature of a nerve graft it is these features
that help clinician choose proper graft for facial nerve

53. Surgical anatomy of facial nerve showing relationship facial nerve to deep tissue plane
especially the superficial musculoaponeurotic system [SMAS]

54. Nerve substitution technique
1. hypoglossal facial nerve crossover technique
2. hypoglossal facial nerve jump graft
3.mini facial nerve cross-face graft
technique

55. Hypoglossal facial nerve crossover technique

56. An incision similar to parotidectomy is made the paratid is
dissected away from facial nerve as it exit stylomastoid foreman te
facial nerve is followed to just past the PES ANSERINUS

57. The descendent hypoglossi is divided with scissors with serrated
blades

58. Epineurium is trimmed proximally and distally exposing
the perineurium

59. Now the hypoglossal nerve is bougtmedial to digastric muscle to
achieve additional length with this maneuver

60. 8-0 monofilament suture placed perineurium out endoneurium
through endoneurium and perineurium out