ENT # Anatomy of Middle ear @ Nerve supply/ Wall of middle ear / Ini cet скачать в хорошем качестве

ENT # Anatomy of Middle ear @ Nerve supply/ Wall of middle ear / Ini cet

ENT – Anatomy of Middle Ear Walls of Middle Ear & Nerve Supply (INI-CET / NEET PG) 1. Middle Ear – Overview • Air-filled cavity in petrous temporal bone. • Also called tympanic cavity. • Extends from tympanic membrane (lateral) to inner ear (medial). • Contains ossicles: Malleus, Incus, Stapes. • Communicates anteriorly with nasopharynx via Eustachian tube and posteriorly with mastoid air cells. 2. Walls of the Middle Ear (6 Walls) Wall Also Called Key Features / Structures Roof Tegmental wall Tegmen tympani; separates middle ear from middle cranial fossa Floor Jugular wall Related to superior bulb of internal jugular vein Lateral Membranous wall Formed mainly by tympanic membrane Medial Labyrinthine wall Promontory, oval window (fenestra vestibuli), round window (fenestra cochleae), fac Anterior Carotid wall Related to internal carotid artery; opening of auditory tube; canal for tensor tympani Posterior Mastoid wall Aditus to mastoid antrum, pyramidal eminence, facial nerve descending part 3. Nerve Supply of Middle Ear • Tympanic plexus present on promontory. • Formed by: • • Tympanic branch of Glossopharyngeal nerve (CN IX) – Jacobson’s nerve (main sensory supply). • • Caroticotympanic nerves from internal carotid sympathetic plexus (sympathetic fibers). • Lesser petrosal nerve carries parasympathetic fibers from tympanic plexus to otic ganglion → parotid gland. • Mucosa of middle ear, auditory tube & mastoid air cells supplied mainly by CN IX via tympanic plexus. 4. INI-CET / NEET PG High■Yield Points • Promontory = bulge of basal turn of cochlea on medial wall. • Oval window attaches to stapes footplate. • Round window closed by secondary tympanic membrane. • Tensor tympani supplied by mandibular nerve (V3). • Stapedius supplied by facial nerve (VII). • Most important sensory nerve of middle ear = Glossopharyngeal nerve (IX).