d. In each inner ear, there are three semicircular canals as well as a utricle and
a saccule. These are concerned with equilibrium. Changing the position of the head
causes movement of fluid within the canals and an impulse is conveyed to the central
nervous system by the vestibular nerve.
Figure 3-27. The ear. (From DeWeese, D. D. and Saunders, W. H., Textbook of
Otolaryngology, 3d edition, St. Louis: The C. V. Mosby Company, 1968.)