Ossicles
size of stapes
3.5 mm long
incus size
7 mm long
size of malleus
8-9 mm long
incudostapedial joint of incus
connection and point of connection with the stapes (articulation of incus and stapes)
head of stapes
connects with lenticular process of incus
head of malleus
connects with the body of the next middle ear ossicle; the incus
short process of incus
projets posteriorly
lenticular process of incus
short process projects posteriorly while long process bends medially, forming lenticular process
4 parts of incus
short process, long process, lenticular process, incudostapedial joint
stapes
smallest bone in body
ossicles
smallest bones int eh body; at adult size at birth
two ways the middle ear overcome impedance mismatch
the area of the tympanic membrane is longer than that of the stapes footplate in the cochlea, so the pressure is concentrated over a smaller area and because of the lever action of the middle ear bones (arm of incus is shorter than that of malleus, producing a lever action that increases the force and decreases the velocity of the stapes)
lateral process of malleus
what produces the bulge on the eardrum when we look otoscopically
oval window
where footplate of stapes is embedded
long process of incus
bends medially
neck of stapes
bicurates to the become the crusa
promontory
bulge created by the basal turn of the cochlea
malleus
connected to tympanic membrane and incus
manubrium of malleus
firmly embedded between the fibrous and mucous membrane layers of the tympanic membrane; most lateral attachment of the ossicular chain
5 parts of stapes
head, neck, anterior crux, posterior crux, footplate
incus
intermediate communicating link for the ossicular chain
footplate of stapes
makes contact with the oval window of the inner ear; embedded into the oval window by the annular ligament; most medial attachment of the ossicular chain
4 parts of malleus
manubrium, lateral process, neck, head
neck of malleus
narrowing between its manubrium and head
round window
opening sealed by the second tympanic membrane and marks the entrance into the scala tympani for the cochlea
