Page 94 - 84 human physiolofy part-1

Chapter 5

Anatomy of the Ear

The ear has three divisions: the outer ear, middle ear, and the inner ear.

Outer Ear (Auricle, Ear Canal, Surface of Ear Drum)
The outer ear is the most external portion of the ear. The outer ear includes the pinna (also called
auricle), the ear canal, and the very most superficial layer of the ear drum (also called the
tympanic membrane). Although the word "ear" may properly refer to the pinna (the flesh covered
cartilage appendage on either side of the head), this portion of the ear is not vital for hearing. The
complicated design of the human outer ear does help capture sound, but the most important
functional aspect of the human outer ear is the ear canal itself. This outer ear canal skin is applied
to cartilage; the thinner skin of the deep canal lies on the bone of the skull. If the ear canal is not
open, hearing will be dampened. Ear wax (medical name - cerumen) is produced by glands in the
skin of the outer portion of the ear canal. Only the thicker cerumen-producing ear canal skin has
hairs. The outer ear ends at the most superficial layer of the tympanic membrane. The tympanic
membrane is commonly called the ear drum.

Middle Ear (Air Filled Cavity behind the Ear Drum, includes most of the Ear Drum, and Ear Bones)
The middle ear includes most of the ear drum (tympanic membrane) and the 3 ear bones ossicles:
malleus (or hammer), incus (or anvil), and stapes (or stirrup). The opening of the Eustachian tube
is also within the middle ear. The malleus has a long process (the handle) that is attached to the
mobile portion of the ear drum. The incus is the bridge between the malleus and stapes. The
stapes is the smallest named bone in the human body. The stapes transfers the vibrations of the
incus to the oval window, a portion of the inner ear to which it is connected. It is the final bone in

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