A manual of anatomy . of the petrous portion of the temporal length is about 18 mm. The lateral canal is placed almost hori-zontally and measures 12 to 15 mm. in length. The posterior canalis about 20 mm. in length. The opposite lateral canals lie in thesame plane while the superior canal of one ear is parallel to the poste-rior canal of the other 354 THE EAR The cochlea represents a tapering tube, of 28 to 30 mm. length,spirally wound for nearly 2^i turns about a bony axis, the broad portion is the base that measures about 9 mm. across and ?is in relation with inf
A manual of anatomy . of the petrous portion of the temporal length is about 18 mm. The lateral canal is placed almost hori-zontally and measures 12 to 15 mm. in length. The posterior canalis about 20 mm. in length. The opposite lateral canals lie in thesame plane while the superior canal of one ear is parallel to the poste-rior canal of the other 354 THE EAR The cochlea represents a tapering tube, of 28 to 30 mm. length,spirally wound for nearly 2^i turns about a bony axis, the broad portion is the base that measures about 9 mm. across and ?is in relation with inferior fossula of the internal auditory end of the coil is the apex, or cupola; it is about 5 mm. abovethe base and about 2 mm. above the apex of the modiolus. Thebasal portion of the tube is about 2 mm. in diameter. The modiolus, or axis is a conical mass about 3 mm. high and ispierced by many foramina for the transmission of nerve the tube side the modiolus sends out a bony shelf that extends. Fig. 256.—Isolated membranous labyrinth of the right side. A, ductus endolymphaticus. about halfway across the tube and is called the lamina spiralisipssea). The division of the tube is completed by the basilarmembrane that extends from the spiral lamina to the lateral wall ofthe osseous tube. As a result two passage-ways are formed, theupper the scala vestibuli and the lower the scala tympani. At themodiolus end of the spiral lamina is a canal that extends the lengthof the shelf and in this spiral canal is lodged the spiral ganglion ofCorti {ganglion spirale). The spiral lamina and basilar membraneextends to within a short distance of the end of the tube and herethe two scalae communicate with each other. This communicationis called the helicotrema. Within the bony labyrinth is a membranous cast called the mem-branous labyrinth {labyrinthicus membranaceous). This cast isseparated from the bony walls by the perilymph. Within the mem-branous labyrinth is the endol
Size: 1825px × 1370px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjecthumananatomy, bookyea
