Anatomy of the Ear
The ear as you know it
Three parts of the ear
Anatomic Subdivisions ◼ External Ear ◼ auricle (pinna) and external auditory canal ◼ Middle Ear (Tympanum) ◼ Tympanic Cavity – TM, ossicles, muscles, connection to eustachian tube ◼ Inner Ear ◼ Membranous Labyrinth – cochlea, saccule, utricle, and semicircular canals
EXTERNAL EAR
External Ear Anatomy Auricle ◼ Helix ◼ Antihelix ◼ Concha ◼ Tragus ◼ Lobule
External Auditory Canal •2.5 cm long •Lateral 1/3 cartilaginous, hairy and ceruminous glands which secrete wax Skin is thick •Medial 2/3 bony, without hairs or ceruminous glands Skin is thin
MIDDLE EAR
Middle Ear Anatomy ◼ Six Walls ◼ Tympanic membrane ◼ Ossicles(three bones) ◼ Muscles ◼ Nerves ◼ Eustachian Tube ◼ Mastoid ◼ Mucosa ◼ ciliated respiratory mucosa with goblet cells ◼ Cuboid mucosa in mastoid
Tympanic Cavity - The Cube ◼ Boundaries ◼ Superior: tegmen tympani ◼ Inferior: air cells and bulb over ◼ Anterior: wall of carotid canal, tensor tympani muscle and canal, eustachian tube orifice ◼ Posterior: pyramidal eminence, chorda tympani entrance, facial recess, facial canal ◼ Medial - promontory , facial ridge ◼ Lateral - TM, scutum Medial Lateral Superior/Roof Inferior/Floor Anterior Posterior