Human anatomy, including structure and development and practical considerations . rvening space filled with afluid, the perilymph, the inner sac lying within the osseous capsule like a shrunkencast within a mould. The membranous labyrinth is hollow and everywhere filledwith a fluid, called the cndo/ymph, which nowhere gains access to the cavityoccupied by the perilymph. The internal ear is closely related, on the one side,with the bottom of the internal auditory canal, which its inner wall contributes, andwith the inner wall of the tympanic cavity on the other. Its entire length is about20 mm.
Human anatomy, including structure and development and practical considerations . rvening space filled with afluid, the perilymph, the inner sac lying within the osseous capsule like a shrunkencast within a mould. The membranous labyrinth is hollow and everywhere filledwith a fluid, called the cndo/ymph, which nowhere gains access to the cavityoccupied by the perilymph. The internal ear is closely related, on the one side,with the bottom of the internal auditory canal, which its inner wall contributes, andwith the inner wall of the tympanic cavity on the other. Its entire length is about20 mm., and its long axis corresponds closely with that of the pyramidal or petrous THK IXTKRXAL I:AR. i^i I portion of the temporal bone. The jjosition of approximately its posterior thirdis indicated by tlie trans\erse rid^e that crosses the npj)er surface of the temporalbone a short distance behind the internal audit(irv meatus. The irregular cavity ofthe bony labyrinth, hollowed out in the temporal bone, comjjrises three subdivis- KiG. 126^. TyinpMiiic cavityIacial canal Cochlea. Semicircular canals Internal auditory canal Rigln temporal bone, upper part of petrous portion has been removed to show bonylabyrinth lying in position. ioiib :— a middle one, the vcs/ibii/c, an anterior one, the cochlea, and a j)ostcrior one,the semicircular canals. Both the front and hind divisions communicate freely withthe vestibule, but neither communicates with the membranous labyrinth nor, in therecent condition, with the tympanic ca\ity. Although corresponding in its generalform with the bony compartments of the cochlea and semicircular canals, themembranous labyrinth less accurately agrees in its contour with the bonv vestibule,since, instead of presenting a single cavity, it is subdivided into two unequalcompartments, known as the saccule and the utricle, which are lodged within thebony vestibule. The divisions of the membranous labyrinth are, therefore, four,which from before backward are :
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Keywords: ., bookauthormc, bookcentury1900, bookdecade1910, booksubjectanatomy
