Download MBBS (Bachelor of Medicine and Bachelor of Surgery) 4th Year (Final Year) ENT Facial nerve Handwritten Notes
? Facial nerve is the nerve of second branchial arch
? It's a mixed nerve, contains motor , sensory & autonomic fibres
? Motor ? muscles of facial expression , platysma ,post belly of
digastric , stylohyoid
? Sensory ?taste sensation from anterior 2\3rd of tongue , smal area
around concha of ear
? Autonomic ? lacrimal , sublingual & submaxil ary glands
NUCLEI
? All four nuclei lie in lower pons
1. Motor nucleus/branchiomotor
2. Superior salivary nucleus
3. Lacrimatory nucleus
4. Nucleus of tractus solitarius
FUNCTIONAL COMPONENTS
? Special visceral /branchial efferent muscles
? General visceral efferent salivary glands , palatal , nasal &
pharyngeal glands
? General visceral afferent afferent impulse from above glands
? Special visceral afferent ant 2/3rd of tongue, soft palate
? General somatic afferent skin of ear
COURSE OF FACIAL NERVE
INTRACRANIAL PART
? Attached to brainstem by two roots motor & sensory( nerve of
Wrisberg ) at the lower border of pons medial to eight nerve in
the cerebellopontine angle
? 15 ? 17 mm in length
? It reach internal acoustic meatus along with vestibulocochlear nerve
INTRA TEMPORAL PART
? MEATAL SEGMENT(15 ? 17 mm)
? LABRYNTHINE SEGMENT( 4 mm)
? Narrowest segment & thin bony canal
? First genu
? TYMPANIC / HORIZONDAL SEGMENT ( 11 mm)
? From geniculate ganglion to pyramidal eminence
? Above oval window & below lateral semi-circular canal
? MASTOID/VERTICAL SEGMENT (13 mm)
? Pyramid to stylomastoid foramen
? Second genu lies between mastoid & tympanic segment
EXTRACRANIAL PART
BRANCHES
? Greater superficial petrosal nerve
? Arises from geniculate ganglion & carries secretomotor fibres to lacrimal gland &
gland of nasal mucosa & palate
? Nerve to stapedius
? Arises from second genu & supplies stapedius
? Corda tympani
? Arises from vertical segment , passes between incus & stapes ,leaves tympanic
cavity through petro tympanic fissure, supplies to submandibular , sublingual ,
brings taste from ant 2/3rd of tounge
? Communicating branch
? Joins auricular branch of vagus & supplies concha ,outer surface of tympanic
membrane, posterior meatus
? Posterior auricular nerve
? Supplies muscles of pinna , occipital belly of occipitofrontalis ,communicates
with auricular branch of Vagus
? Muscular branches
? Stylohyoid ,posterior belly of digastric
? Peripheral branches
? Upper temporofacial
? Lower cervicofacial
? Peripheral branches ( pes anserinus )
? Temporofacial
? Temporal
? Auricularis anterior
? Auricularis superior
? Frontalis
? Orbicularis oculi
? Corrugator supercilia
? Zygomatic
? Orbicularis oculi
? Cervicofacial
? Buccal
? Two branches ? upper & lower buccal ,supplies muscles in vicinity mainly
buccinator
? Marginal mandibular
? Muscles of lower lip ? orbicularis oris , mentalis ,depressor labi anguli etc
? Cervical
? Platysma
This post was last modified on 11 August 2021