Ear Flashcards
External Ear
Helix and Anti Helix
Tragus and Anti Tragus
External Acoustic Meatus
Concha of auricle to tympanic membrane
Lateral 1/3 cartilaginous, S shaped
Medial 2/3 is bone
Ceruminous and sebaceous glands produce cerumen
Innervation of External Acoustic Meatus
Auriculotemporal
CN 7 and 10
Tympanic Membrane
Umbo-central depression
Cone of light radiates anteroinferiorly
Tympanic Membrane Innervation
External surface = Auriculotemporal (V3)
Internal surface = Glosso (CN 9)
Middle Ear
Anteriorly connected to nasopharynx by pharyngotympanic tube
Posterosuperiorly connected to mastoid air cells
Middle Ear Contents
Stapedius Tensor Tympani Ossicles Chorda Tympani Tympanic Plexus
Ossicles
Malleus
Incus
Stapes
Malleus
Mallet or Hammer
Head, neck, handle
Tensor Tympani (V3) inserts on handle to reduce amplitude of oscillations
Chorda Tympani cross on medial surface of neck
Incus
Anvil
Lies within the epitympanic recess
Stapes
Stirrup
Sits on oval window of inner ear
Roof of Middle Ear (Tympanic Cavity)
Tegmen tympani portion of temporal bone
Floor of Middle Ear (Tympanc Cavity)
Separates tympanic cavity from jugular foramen and IJV
Lateral wall of Middle Ear
Tympanic Membrane
Malleus
Chorda Tympani
Medial Wall of Middle Ear
Separates tympanic cavity from inner ear
Promonotory
Oval window with stapes
Round window
Anterior Wall of Middle Ear
Separates tympanic cavity from carotid canal and internal carotid artery
Auditory tube and canal for tensor tympani
Posterior Wall of Middle Ear
Air cells within mastoid antrum
Facial canal
Pyramidal eminence for stapedius (CN 7)
Pharyngotympanic Tube
Auditory or Eustachian Tube
Connects middle ear to nasopharynx
Posterolateral 1/3 is bony, rest is cartilaginous
Equalizes pressure in middle ear
Internal Ear - Bony Labyrinth
Cochlea
Vestibule
Semicircular Canals
Internal Ear - Membranous Labyrinth
Cochlear Duct
Saccule and Utricle
Semicircular Ducts
Endolymphatic Duct and Sac
Internal Ear - Cochlea
Produces promonotory on medial wall of middle ear cavity, basal turn
Cochlear duct is suspended by fluid inside
Internal Ear - Vestibule
Saccule and Utricle are suspended within it
Endolymphatic duct to endolymphatic sac
Internal Ear - Semicircular Canals
Anterior, Posterior, Lateral
- Set at right angles to each other, 3 planes of space
Communicate with vestibule
Semicircular ducts are suspended with them
Internal Ear - Internal Acoustic Meatus
Entrance of CNs 7 and 8 from posterior cranial fossa into inner ear
Otitis Media
Myringotomy
Meniere Syndrome
Increase endolymphatic fluid volume
Tinnitus, hearing loss, veritgo
Hyperacusis
Loss of CN 7