BLOOD VESSELS OF THE INTERNAL EAR. 



39 1 



diictus 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 

 ;< na aquaeductus cochleae receives blood from parts of the utriculus, saccu- 

 lus and cochlea; it passes through a bony canal to the internal jugular vein. 

 Within the cochlea it arises, as shown in Fig. 440, from small vessels 

 including the vas prominens (a) and the vas spirale (b). Branches derived 

 from these veins pass toward the modiolus. (There are no vessels in the 



Scala tympa'ni. Scala vestibuli. 



Str 



isc ul 



Cross section of a spiral 

 artery of the modiolus. 



Vena laminae spiralis. 



Ganglion spirale. 



Vena spiralis superior. 



Cross section of a spiral 

 artery of the modiolus. 



Vena laminae spiralis. 

 Anastomosis. 



" Vena spiralis inferior. 



FIG. .440. DIAGRAM OF A SECTION OF THE FIRST (BASAL) AND SECOND TURNS OF THE COCHLEA. 

 a, Vas prominens; b, vas spirale. 



vestibular membrane of the adult, and the vessels in the wall of the sea la 

 tympani are so arranged that only veins occur in the part tow r ard the mem- 

 branous 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 turn of the cochlea, and a 

 superior spiral vein which proceeds from the apical portion. These two 

 spiral veins unite with vestibular branches to form the vena aquaeductus 

 cochleae (Fig. 439). 3. The internal auditory vein arises within the 



