The document discusses the facial nerve (cranial nerve VII) in three paragraphs or less: The facial nerve controls muscles of the face and allows for facial expressions. It has both motor and sensory components that originate from different embryonic structures and nuclei. The nerve exits the skull through the stylomastoid foramen and gives off five terminal branches innervating various facial muscles. Facial nerve palsy can result from lesions along the nerve's course and have varying clinical presentations depending on the location of injury. Common causes include Bell's palsy, tumors, trauma, and infections. Differential diagnosis and management involve identifying the underlying etiology.

1. FACIAL NERVE
and APPLIED
ANATOMY
- Divvi Anusha
1st Year PG, Public Health
Dentistry
FACIAL NERVE AND APPLIED ANATOMY
By
DIVVI ANUSHA
1st year MDS
DEPT OF PUBLIC HEATH
DENTISTRY

2. CONTENTS
• Introduction
• Embryology
• Structure
• Course
• Branches and Distribution
• Applied aspect
• References

3. INTRODUCTION
• The facial nerve – 7th nerve and is mixed
• This nerve allows us to laugh, cry, smile, frown hence
known as “The Nerve of Facial Expression”
(BUNNELL 1927).
• In 1821-Sir Charles Bell

4. • Mixed nerve only when it is inside the skull
• After leaving the skull it becomes a purely motor
• More important as a motor nerve than as a sensory
nerve.

5. EMBRYOLOGY
• Derived from second pharyngeal arch.
• The motor division- basal plate of the embryonic
pons
• Sensory division from the cranial neural crest
• 3rd week of gestation – facioacoustic primordium
gives rise to VII and VIII cranial nerves

6. • 4th week – chorda tympani descends from the main
branch.
• 5th week – geniculate ganglion, nervous intermedius,
greater petrosal nerve appears.
• 7th and 8th weeks – 2nd branchial arch gives rise to
muscles of facial expression.

7. • 11th week – facial nerve is fully developed.
• Nerve fibres for taste are supplied by chorda
tympani branch of facial nerve
• supplies motor and sensory innervations to the
muscles formed by hyoid arch

9. STRUCTURE
• Two roots – sensory root and motor root.
• Sensory Root: Also called as nervous intermedius.
• Conveys gustatory fibres from anterior 2/3rds of the
tongue

10. • Secretory and vasomotor fibres to :
lacrimal gland
submandibular and sublingual salivary
glands
glands of nasal and palatine mucosa.
• Cutaneous sensory impulses from external
auditory meatus and the region back of the ear.

12. • Motor root: Largest root
• Supplies muscles of face, scalp and auricle, the
buccinator, platysma, stapedius, stylohyoid and
the posterior belly of digastric.

13. NUCLEI OF FACIAL NERVE
• The fibres of facial nerve are connected to four nuclei
• 1) Motor nucleus: divided into lateral, intermediate
and medial leminsci
• Lateral portion supplies muscles around the mouth
and buccinator

14. • Intermediate portion supplies muscles of upper
face including orbicularis oculi.
• Medial portion supplies the stapedius, stylohyoid,
posterior belly of digastric, platysma and
occipitofrontalis.

16. 2) Nucleus of Tractus Solitarius:
Special sensory nucleus
Brings sensations from the anterior 2/3rds of tongue
and palate.
3) Superior Salivatory Nucleus:
Parasympathetic nucleus
Secretomotor fibres to glands

17. 4) Upper part of nucleus of the spinal tract of the
Trigeminal nerve:
Receives sensation of skin of EAM via auricular
branch of vagus nerve.

18. COURSE
The path of facial nerve can be divided in to six
segments.
1) Intracranial segment: Motor part arises from the
facial nucleus
sensory and parasympathetic parts from sensory
nucleus and superior salivatory nucleus
2) Meatal segment: Enters the petrous temporal bone
via internal auditory meatus.

22. 3)Labyrinthine segment: Short and contains geniculate
ganglion.
4) Tympanic segment: Facial nerve runs through the
tympanic cavity
5) Mastoid segment: Pyramidal eminence
Chorda tympani and nerve to stapedius in the temporal
part.
6) Extratemporal segment: Emerges out from
stylomastoid foramen and gives five terminal branches.

23. BRANCHES and DISTRIBUTION
• A) Within the facial canal
1. Greater petrosal nerve: carries preganglionic
presympathetic fibres to the lacrimal, nasal and
palatine glands.
2. The nerve to the Stapedius muscle: supplies the
stapedius muscle

25. 3) The Chorda tympani: carries preganglionic
secretomotor fibres to the submandibular ganglion
and taste fibres from the anterior 2/3rds of the
tongue
B.As it exit from the stylomastoid foramen:
1) The posterior auricular nerve: supplies
auricularis posterior, occipitalis, intrinsic muscles on
the back of the auricle.

26. 2) The nerve to the posterior belly of digastric:
supplies posterior belly of digastric.
3) The nerve to the stylohyoid muscle: supplies the
stylohyoid muscle.
C) Temporal branches within the parotid gland
1. Temporal nerve: supplies occipitofrontalis,
orbicularis oculi, corrugator supercilli

29. 2. The zygomatic nerve: upper zygomatic supplies
orbicularis oculi
lower zygomatic supplies muscles between eye
and mouth and muscles of nose.
3. The buccal nerve: supplies buccinator and
orbicularis oris muscles.

30. • 4. The marginal mandibular nerve: supplies the
muscles of lower lip and chin
• 5. The cervical nerve: supplies the platysma muscle
• D) Communicating branches with adjacent cranial
and spinal nerves

31. GANGLIA
The ganglia associated with the facial nerve are as
follows:
1. The geniculate ganglion:
Located on the first bend of facial nerve
Sensory ganglion
2. The submandibular ganglion:
Parasympathetic ganglion
Relay of secretomotor fibres to the submandibular
and sublingual glands

32. 3. The pterygopalatine ganglion:
Parasympathetic ganglion
Relay of secretomotor fibres to the lacrimal gland

33. APPLIED ANATOMY
Disorders of facial nerve:
1. Supranuclear lesions
Features:
 Paralysis of lower part of face (opposite side)
 Partial paralysis of upper part of face
 Normal taste and saliva secretion
 Stapedius not paralysed

34. 2. Infranuclear lesions
Features:
 Paralysis of facial muscle (same side)
 Paralysis of lateral rectus
 Internal strabismus

36. Localization of Peripheral lesions
a) At the Internal acoustic meatus
Features:
 Paralysis of secretomotor fibers
 Hyper acusis
 Loss of corneal reflex
 Taste fibers unaffected
 Facial expression and movements paralysed

37. b) Injury distal to geniculate ganglion
Features:
 No hyper acusis
 Loss of corneal reflex
 Taste fibers affected
 Facial expression and movements paralysed

38. c) Injury at the Stylomastoid foramen
Condition known as bells palsy

39. First described more than a century ago by Sir
Charles Bell.
Yet much controversy still surrounds its etiology and
management.
Bell’s palsy is certainly the most common cause of
facial paralysis worldwide.

40. Features of Bell’s Palsy
 Unilateral involvement
 Inability to smile, close eye or raise eyebrow
 Drooping of corner of the mouth
 Inability to close eyelid (Bell’s sign)
 Inability to wrinkle forehead
 Slurred speech
 Mask like appearance of face
 Loss/ alteration of taste

41. CAUSES OF FACIAL NERVE
PARALYSIS
1. Birth Causes :
Facial Nerve Injury from Birth Trauma
 Trauma (forceps delivery)
 Congenital Facial Palsy:
a) Moebius syndrome
b) Cardiofacial syndrome

42. 2. Infections:
 Herpes zoster virus
 Acute or chronic otitis media
 Lyme disease caused by Borrelia burgdorferi
 HIV infection
 Mastoiditis
 Skull base osteomyelitis
 Meningitis
 Syphilis

43. 3. Trauma :
 Cortical injury
 Temporal bone fracture
 Brain stem injury

44. 4. Tumours :
 Facial Nerve neuroma
 Cholesteatoma
 Meningiomas
 Hemangioblastoma
 Hemangioma
 Pontine glioma
 Parotid tumor

46. 5. Endocrine causes
 Diabetes Mellitus
 Hyperthyroidism
 Pregnancy
 Hypertension

47. 6. Iatrogenic causes
 Mandibular block anesthesia
 Head and neck surgery

48. Differential diagnosis of facial paralysis
 Syndromes associated with facial paralysis
 Stroke
 Syphilis
 Lyme disease
 Granulomatous diseases
 Otitis media
 Multiple sclerosis
 Tumours

49. Syndromes associated with facial paralysis
1. Guillain-Barre syndrome
Features
 Bilateral facial paralysis
 Difficulty with bladder control or bowel function
 Rapid heart rate
 Low or high blood pressure
 Difficulty breathing

50. 2. Ramsay Hunt syndrome type II
Features:
 Facial paralysis
 Ear pain
 Vesicles
 Hearing loss
 Vertigo

51. 3. Moebius syndrome
 Abnormal VI ,VII,XII Nerve nuclei
 Facial Nerve absent or small
 Congenital Extra ocular muscle and facial palsy

52. 4. Cardiofacial syndrome
• Unilateral facial paralysis involving only the lower
lip and congenital heart disease

53. 5. Treacher collins syndrome
The OMENS classification
O- orbital asymmetry
M- mandibular hypoplasia
E- auricular deformity
N- nerve development
S- soft-tissue disease

54. Facial Nerve involvement in Treacher collins
syndrome
 N0: No facial nerve involvement
 N1: Upper facial nerve involvement
 N2: Lower facial nerve involvement
 N3: All branches affected

55. 6. Goldenhars syndrome
• Involves structures arising from the first and
second branchial arches
• Features of hemi facial microsomia,vertebral
anomalies, congenital facial nerve palsy.

56. 7. Melkersson Rosenthal syndrome
It is a rare neurological disorder characterized by :
 Recurring facial paralysis
 Swelling of the face and lips (usually the upper
lip)
 Development of folds and furrows on the tongue

57. 8. Heerfordt’s syndrome
Is a rare manifestation of sarcoidosis
Features:
 Inflammation of the eye (uveitis)
 Swelling of the parotid gland
 Chronic fever
 In some cases, palsy of the facial nerves

58. 9. Gradenigo syndrome
• It is a complication of otitis media and mastoiditis

59. MANAGEMENT OF FACIAL PARALYSIS
Medical treatment
Corticosteroids :
Prednisolone 1 mg/kg/day 7-10 days
Corticosteroids combined with antiviral drug is
better
Acyclovir 400 mg 5 times/day
Famcyclovir and valacyclovir 500 mg bid

60. Surgical treatment
 Nerve repair or nerve grafts
 Nerve transposition
 Muscle transposition or sling procedures
 Muscle transfers
 Ancillary eyelid or oral procedures
 Now-a-days monochromatic infrared energy is
used

61. CONCLUSION
• Surgeons have to pay attention to minimize the
risk of complications
• The patient has to be informed beforehand

62. REFERENCES
• Gray’s Anatomy 42nd edition
• B D Chaurasia’s Human anatomy Vol 3
• AK Dutta’s Essentials of human anatomy

63. THANKYOU