Fig. 10 VIEW OF THE DEEP STRUC-
TURES OF THE HEAD SHOWING TOPOGRAPHICAL RELATIONSHIPS OF THE INTERNAl EAR TO OTHER PARTS OF THE AUDITORY APPARATUS AS WELL AS TO THE CRANIAL CAVITY, ARTERIES, VEINS, PHARYNX AND NOSE

The plane of this figure passes through the compact petrous pyramid of the temporal bone, revealingthe labyrinth or inner ear lodged in it. The latterc onsists of the cochlea (86) and the vestibule (85). The cochlea, containing terminations of the auditory branch of the eighth cranial nerve, is a specific peripheral organ of hearing. The vestibule composed of two minute pouches, the utricle and the saccule, and of three semicircular canals, contains terminations of the vestibular branch of the eight hnerve and is a specific peripheral organ of equilibrium. (For further details, see Part II). The important structures immediately adjoining the petrous bone are the large internal carotid artery (25b) and the internal jugular vein (12b), the principal vessels ofthe cerebrum. Even more intimate is the relationship of the facial nerve (VII) which is enclosed in a channel within the temporal bone.