Middle Ear

Question 1

where does the middle ear begin at

Answer 1

tympanic membrane (cone shaped)

Question 2

what is the annulus

Answer 2

holds the tympanic membrane in place, attached to a groove in the temporal bone called the tympanic sulcus

Question 3

notch of Rivinus

Answer 3

small discontunuity to accomodate a tiny interruption in the tympanic sulcus

Question 4

3 layers of the tympanic membrane

Answer 4

outer layer, continuos with ear canal
inner layer, continuous with mucous membrane lining of middle ear
middle layer is fibrous tissue

Question 5

tympanic cavity

Answer 5

air filled cavity in the middle ear

Question 6

where it the tympanic cavity located

Answer 6

petrous portion of the temporal bone
1/2 high x 1/2 wide x 1/4 deep
volume is 2 cm3

Question 7

3 portions of the tympanic cavity

Answer 7

1. epitympanic recess or attic
2. mesotympanum
3. hypotympanum

Question 8

epitympanic recess (attic)

Answer 8

superior portion of tympanic cavity head of malleus and incus

Question 9

mesotympanus

Answer 9

middle portion of tympanic cavity, rest of ossicular chain

Question 10

hypotympanum

Answer 10

inferior portion of tympanic cavity
below the inferior portion of annulus
below eustachian tube

Question 11

what are the ossicles

Answer 11

malleus (hammer)
incus (anvil)
stapes (stirrup, smallest bone in body)

Question 12

malleus

Answer 12

consist of the head, neck and ant. lat. and manubrium processes

Question 13

how are the ossicles suspended in the middle ear cavity

Answer 13

series of muscles and ligaments

Question 14

annular ligament

Answer 14

ligament that holds the stapes footplate in the oval window

Question 15

ligaments of the middle ear

Answer 15

sup ligament of the malleus
ant. ligament of malleus
lateral ligament of malleus
sup. ligament of the incus
post. ligament of incus
annular ligament of the stapes

Question 16

tegmen tympani

Answer 16

paper thin plate of bone separating the middle ear from the cranial cavity

Question 17

aditus ad antrum

Answer 17

narrow bony passageway that connects the tympanum to the antrum

Question 18

pyramidal eminence

Answer 18

contains the stapedius muscle

Question 19

fossa incudis

Answer 19

small evacuation in lower and back portion of epitympanic recess that accommodates the short process of the incus

Question 20

3 functions of the outer ear

Answer 20

sound transmission/enhancement
sound localization cues
middle ear protection