Anatomy

Question 1

Landmarks of Outer ear (Pinna/auricle)

Answer 1

helix - archway defining top of outer ear
scaphoid fossa - flat area under helix
tragus - face-side of opening
lobe - epithelial cells

Question 2

External Auditory Meatus (EAM)

Outer ear

Answer 2

canal that is curved upward (s shaped)
entering temporal bone when you enter the tube
water/foreign matter flows outward
cilia and sebacious glands produce cerumen (wax) that traps impurities

Question 3

Tympanic membrane (ear drum)
middle ear

Answer 3

At the end of the EAM
Shaped like a concave drum stretched across and attached to bony frame that sits in a groove in temporal bone
3 layers - middle is toughest, outer ones mend with ear
Most membrane is tough, top is loose
Membrane is smooth and grayish, one reflects light (cone of light)
Malleus handle casts a white streak from center called umbo

Question 4

Tympanic cavity

Answer 4

In the middle ear (air filled cavity)
Contains the malleus and incus
Posterior wall - hole that opens to mastoid air cells
Roof of cavity is paper thin

Question 5

Medial wall landmarks

Answer 5

Oval window - entrance to inner ear, covered by oval footplate of the stapes
Above is a prominence caused by facial nerve passing through temporal bone
Below is a bony projection - promontory
Round window - below promontory, covered by a membrane

Question 6

Eustachian tube

middle ear

Answer 6

Floor of middle ear is open and leads to this, leads to the nasopharynx
Tube slides down, anteriorly and medially
Tube can be easily clogged in nasopharynx
Brings air pressure of nasopharynx to middle ear - air pressure on both sides of TM is equal, facilitates vibration of ear drum
If air pressure changes suddenly, takes time to go back - airplane

Question 7

Ossicles

middle ear

Answer 7

Malleus - mallot/hammer - has a head, neck (manubrium), and a handle
Incus - anvil - 2 legs, one shorter and an articular surface (place of contact) where head of malleus swivels
Stapes - stirrup - head, 2 legs (crus), and oval footplate

Question 8

Ossicles 2

middle ear

Answer 8

Held in place loosely by a series of ligaments
-Superior/lateral/anterior malleolar ligament
-Posterior incal ligament
-Elastic annular ligament
Malleus and incus meed in diarthroidal joint
Incus and stapes meet in a ball and socket joint