MICROSCOPIC ANATOMY oh' THE OR(iA^s 



ganglion spirale, some for the lamina spiralis, and some for 

 the walls between the scalse. The last branches mentioned 

 run to the stria vascularis, where they form a rich network 

 of capillaries. 



Of the capillary networks which arise from these arteries 

 of the membranous labyrinth, those of the maculae and crista* 

 are the densest. 



The venous blood escapes from the membranous labyrinth 

 by three separate venous trunks : 



(a) The vena aquceductus vestibuli collects the blood from 

 the semicircular canals and partly from the utriculus. 



FIG. 273. 



Cochlea of human adult, showing blood-vessels. < 



V, veins. 



(After Eichlcr. i A, arteries; 



(b) The vena aquceductus cochlew carries the blood from a 

 part of the utriculus, the sacculus, and the cochlea. The veins 

 of the cochlea run mainly in the walls of the scala tympani. 

 They unite to form the vena spir ales, which lie under the spiral 

 ganglion. We distinguish two spiral veins : the lower (pos- 

 terior) collects the blood from the first and part of the second 

 coil of the cochlea; the upper (anterior) drains the upper 

 segments of the cochlea. 



The above-mentioned vas prominens, as well as the vas 

 spirale which runs in the tympanal layer of the membrana 



