Page 252 - Anatomy and Physiology of Farm Animals, 8th Edition

Sense Organs / 237

Auricle
VetBooks.ir External auditory Auditory ossicles

canal
A. Malleus
B. Incus
C. Stapes (abuts vestibular window)
External ear
Semicircular ducts
within semicircular canals

Inner ear

Vestibulocochlear
nerve
Ampulla

B Utriculus
A Sacculus
C
Cochlea

Cochlear duct

Opening into
auditory tube

Tympanic cavity
Auditory
tube
Tympanic membrane

External ear Middle ear
Figure 12-6. Anatomy of the hearing and vestibular apparatus. External, middle (blue), and internal
(pink) ears with surrounding temporal bone. Auditory ossicles (red) span the middle ear from the
tympanic membrane to the inner ear.

rostral and caudal auricular muscles; these ceruminous glands. The combined secretion
are all innervated by the facial nerve. of these glands is called cerumen, a brown
A tubular extension of the pinna, the waxy substance that protects the canal.
cartilaginous external acoustic canal, A separate annular cartilage adjacent to
extends from the pinna to the tympanic the funnel‐shaped base of the auricular
membrane. The external acoustic canal is cartilage forms most of the external acoustic
lined with a modified skin possessing canal. A third cartilage, the scutiform carti­
few hairs and abundant sebaceous and lage, lies medial to the auricular cartilage,