EAR 



477 



The veins of the labyrinth form three groups (Fig. 481). i. The vena 

 aqu&ductus vestibuli receives blood from the semicircular ducts and a part 

 of the utriculus. It passes toward the brain in a bony canal along with 

 the ductus endolymphaticus, and empties into the superior petrosal sinus. 

 2. The vena aquaductus cochlea receives blood from parts of the utriculus, 

 sacculus and cochlea; it passes through a bony canal to the internal 

 jugular vein. Within the cochlea it arises, as shown in Fig. 482, from 



Ductus semicircularis 

 superior. 



Ampulla lateralis. 



f Arteria vestibulans. 

 [ Arteria cochlearis. 



Ampulla 

 posterior. 



Ductus semicircularis 

 posterior. 



Arteria 

 cochlearis. 



Vestibulo-cochlear 



branch of the 

 arteria cochlearis. 



Vena aquseductus cochlea. 



PIG. 481. DIAGRAM OF THE BLOOD VESSELS OF THE RIGHT HUMAN LABYRINTH. MEDIAL AND POSTERIOR ASPECT. 

 D, c., Ductus cochlearis; S., sacculus; U., utriculus; i, ductus reuniens; 2, ductus utriculo-saccularis. The saccus 



endolymphaticus is cut off. 



small vessels including the vas prominens (a) and the vas spirale (6). 

 Branches derived from these veins pass toward the modiolus. (There are 

 no vessels in the vestibular membrane of the adult, and the vessels in the 

 wall of the scala tympani are so arranged that only veins occur in the part 

 toward the membranous spiral lamina; thus the latter is not affected by 

 arterial pulsation.) Within the modiolus the veins unite in an inferior 

 spiral vein, which receives blood from the basal and a part of the second 

 turns of the cochlea, and a superior spiral vein which proceeds from the 



