1060 



ORGANS OF SPECIAL SENSE 



cochlear recess of the vestibule in a blind pouch, the vestibular caecum, and travers- 

 ing the spiral canal of the cochlea, ends just beyond the hamulus of the lamina spir- 

 alis in a second blind pouch, the cupular caecum. Close to the vestibular caecum 



FIG. 757. SCHEMATIC REPRESENTATION OF THE RIGHT MEMBRANOT-S LABYRINTH AND THE 

 DIVISIONS OF THE ACOUSTIC NERVE. Dorsal view. (Toldt, "Atlas of Human Anatomy," 

 Rebmiin, London and New York.) 



UTfllCULO-SACCULAR DUCT 

 MACULA ACUSTICA OF UTRICLE 

 MACULA ACUSTICA OF SACCULE 

 VESTIBULAR GANGLION 



VESTIBULAR XEl:\'K 

 SACCULAK NERVE 



COCHLEAR NERVE -_ 



COCHLEAR DUCT 



SACCULE 

 DUCTUS REUNIENS (OF HENSEN) .- 



POSTERIOR AMPULLARY NERVE 



- SUPERIOR SEMICIRCULAR DUCT 



AMPULLARV CRISTA OF THE SUPE- 

 .. RIOR AND LATERAL SEMICIRCULAII 

 DUCTS 



- LATERAL SEMICIRCULAR OUCT 



ENDOLYMPHATIC DUCT 



POSTERIOR SEMICIRCULAR 

 DUCT 



AMPULLARY CRISTA OF THE 

 POSTERIOR SEMICIRCULAR 

 DUCT 



ENOOLYMPHATIC SAC 



it is joined to the saccule by the ductus reuniens. It is lined throughout by epi- 

 thelium and is somewhat triangular in cross-section. Its floor is formed by thickened 

 periosteum over part of the osseous lamina spiralis and by a fibrous membrane, the 



FIG. 758. AXIAL SECTION THROUGH THE DECALCIFIED COCHLEA OF A NEWBORN CHILD. 

 (Toldt, "Atlas of Human Anatomy," Rebman, London and New York.) 



Hamulus of lamina spiralis ^ 

 A 

 Apical splrtti 



Middle spiral -- 

 Basal spiral 



Vestibular membrane 



Lamina basilaris (mem- 

 branous lamina spir- 

 al! a) 



Osseous lamina spiralis 



SPIRAL GANGLION OF COCHLEA 



Base of modioluB 



COCHLEAR XER\'E 



Internal acoustic meatus 



Helicotrema 



Modiolug 



/ Scala vestibuli 



Cochlear duet 



\\ \\ - Spiral ligament of cochlea 

 /'\\35s> "% \ ' .' -..- Scala tympani 





ACOUSTIC NERVE (cochlear dirislon) ' 



Perilymphatic space of 

 veeiibule 



--Macula acustica sacculi 

 SaJt-- Wall of saccule 



sACCTLAfi M-xri-; 



jf~- VESTIBTLAR 

 GANGLION 



ACOUSTIC NERVE (mstib- 

 iiitir diiision) 



lamina basilaris, which stretches from the free border of the lamina spiralis to a 

 thickening of the periosteum, the spiral ligament of the cochlea, on the peripheral 

 wall. The epithelium of this floor is greatly modified, forming the spiral organ 



