Outer, Middle, and Inner Ear Anatomy, Auricle, External Acoustic Meatus, Tympanic Membrane, Ossicles (Malleus, Incus, Stapes), Stapedius & Tensor Tympani Reflex, Pharyngotympanic Tube, Middle Ear Muscles, Cochlear Duct, Scala Vestibuli & Tympani, Organ of

Outer, Middle, and Inner Ear Anatomy, Auricle, External Acoustic Meatus, Tympanic Membrane, Ossicles (Malleus, Incus, Stapes), Stapedius & Tensor Tympani Reflex, Pharyngotympanic Tube, Middle Ear Muscles, Cochlear Duct, Scala Vestibuli & Tympani, Organ of Corti, Hair Cells, Vestibule & Semicircular Canals, Utricle & Saccule, Perilymph & Endolymph, Internal Acoustic Meatus, Labyrinth Artery, Auditory Pathway, Conductive vs Sensorineural vs Central Hearing Loss, Weber & Rinne Tests, BPPV & Epley Maneuver, Otoliths, Basilar & Tectorial Membranes Exam Questions Verified with A+ Graded Rationales Latest Updated 2026 Function of outer and middle ear collect and amplify sound waves and transfer sound waves into the inner ear Function of inner ear - converts sound waves from outer/middle ear and turns them into neurological impulses - also involved in balance (equilibrium) Parts of the External ear Auricle (pinna) External acoustic meatus (EAM) Tympanic membrane What gives blood supply to the auricle? external carotid artery - posterior auricular - superficial temporal arteries ** Remember maxillary is also a branch off of ECA but it doesn't play big role here** External Auditory Meatus Function Difference in composition for medial vs lateral EAM - Conducts sound from auricle to tympanic membrane causing tympanic membrane to VIBRATE Medial: bony "ectotympanic tube" Lateral: cartilaginous What ear bone is visible through the tympanic membrane? (HY/TQ) malleus - lateral process - handle What innervates the OUTER surface of the tympanic membrane? What innervates the INNER surface of the tympanic membrane? Auriculotemporal n. (V3) auricular branch of vagus n. Glossopharyngeal n. (CN IX) Somatosensory Innervation What innervates Medial surface of TM & rest of middle Ear? Tympanic Branch of Glossopharyngeal nerve (CN 9) Somatosensory Innervation What innervates the skin of the external ear? Auriculotemporal n. (V3) -tragus, parts of EAM, outer eardrum Great Auricular n. -helix, lobule, lower cranial surface What should the tympanic membrane look like? Clinical Correlation translucent, pearly gray color projects reflection from otoscope light Should see a "cone of light" Middle Ear Significance of CN7 and CN9 Tympanic n (from CN 9) goes up into middle ear cavity and escapes from the roof of the cavity as lesser petrosal nerve (eventually goes to parotid gland)! CN7 leaves the skull Contents of the Middle Ear Tympanic Membrane Chorda Tympani Auditory Tube Mastoid Antrum