Ear Anatomy Flashcards
What provides the blood supply to the external ear?
Posterior auricular A.
Superficial temporal A.
What innervates the external surface of the Tympanic membrane?
Auricular branch of Vagus N.
Auriculotemporal N. (CN V3)
What innervates the internal surface of the tympanic membrane?
Glossopharyngeal N. (CN IX)
What is the innervation of the external ear?
Great Auricular (C2/C3) - Most of cranial surface)
Auriculotemporal N. (V3) - Tragus and anterior wall of external acoustic meatus
Vagus N (Auricular branch) - External acoustic meatus
Facial N - small areas within the concha
Between what layers in the ear does an Auricular hematoma collect?
Perichondrium and cartilage
A patient presents with otitis externa. Where is their infection located?
External Acoustic Meatus
What is the physical composition of the External Acoustic meatus?
Lateral 1/3 - cartilage
Medial 2/3 - bone
When visualizing the tympanic membrane, where is the cone of light located?
Anterior/Inferior
What bone of the middle ear is embedded in the tympanic membrane?
Malleus (handle and umbo)
In otitis media, why does the tympanic membrane appear red and bulging?
Inflammation and swelling in the middle ear can block the pharyngotympanic tube => Fluid buildup in middle ear => Bulging
What kind of deafness results from a ruptured tympanic membrane?
Conduction deafness
When would a myringotomy procedure be performed? What are the steps?
Otitis media
- Incision of ear drum
- Aspiration of fluid
What is a tympanostomy?
Ear tube placement
What does the Tegmen Tympani keep the middle ear separate from?
Brain/middle cranial fossa
What does the jugular wall keep the tympanic cavity separate from?
Bulb of Internal jugular V.
What does the Labrinthine wall keep the tympanic cavity separate from?
Inner Ear
What middle ear bone pushes on the oval window?
Stapes
What does the mastoid wall keep the tympanic cavity separate from?
Mastoid air cells
Facial canal
What does the anterior wall keep the tympanic cavity separate from?
Internal Carotid A.
What wall of the tympanic cavity are the opening for pharyngotympanic tube and canal for tensor tympani located?
Anterior wall
What wall are the oval window, round window, and promontory located on in the tympanic cavity?
Medial (Labrinthine) wall
What does the tensor tympani M. insert onto in the middle ear?
Malleus (handle)
What part of the stapes does the stapedius M. insert onto?
Neck
What muscles of the ear prevent damage from loud sounds?
Tensor Tympani M.
Stapedius M.
What innervates Tensor Tympani M.?
CN V3
What innervates Stapedius M.?
CN VII
What part of the inner ear is located within the petrous part of the temporal bone?
Bony Labyrinth
The semicircular canals of the inner ear are filled with what fluid?
Perilymph
The membranous labyrinth of the inner ear is filled with what fluid?
Endolymph
What part of the membranous labyrinth senses gravity?
Utricle and saccule
What part of the membranous labyrinth senses acceleration?
Semicircular ducts
What part of the membranous labyrinth senses hearing?
Cochlear labyrinth/duct
What artery supplies the inner ear?
Internal/Labyrinthine A.
What part of the Membranous Labyrinth contains Cochlear N.?
Basilar Membrane
What membrane are the hair cells of the cochlea embedded in?
Tectorial Membrane
