204 Anatomy of the Rabbit. 



urethra. The main vessel leaves the pelvic cavity as the 



sciatic artery (a. ischiadica), passing fo the lateral side 



of the abductor caudae anterior, and reappears posteriorly, 



dividing into the internal pudendal and lateral caudal 



arteries. 



3 The inferior caval vein (v. cava inferior) is formed on the 



dorsal surface of the posterior end. of the aorta by the union of the 



paired external iliac veins with the common hypogastric. From 



this position it passes to the right side of the aorta (rarely to the 



left) almost to its ventral surface, arid then runs forward on the 



right side to the diaphragm. Its visceral roots or tributaries 



(radices viscerales) comprise the paired renal and spermatic 



veins, and the hepatic veins from the liver (p. 188). Its parietal 



tributaries (radices parietales) include the inferior phrenic 



veins (w. phrenicae inferiores), which enter the inferior cava from 



either side of the diaphragm, the lumbar veins (vv. lumbales), 



a series of vessels corresponding to the lumbar arteries, and the 



paired iliolumbar vein (v. iliolumbalis). 



4. The external iliac vein (v. iliaca externa), the continuation 

 of the femoral vein of the thigh, approaches the inferior cava from 

 the dorsal side of the inguinal ligament. It receives the inferior 

 epigastric vein from the abdominal wall and the vesical vein 

 from the bladder, the latter including in the female also the veins 

 of the uterus. 



5. The sympathetic trunk (truncus sympathicus). Its lum- 

 bar and sacral portions, and, with due care, its caudal portions may 

 be traced, on either side by working between the abdominal aorta 

 (or its continuation, the median sacral artery) and the body-wall. 

 Except on the ventral surface of the sacrum, the ganglia of opposite 

 sides lie close together. The lumbar portion of each trunk 

 comprises seven ganglia with their connections. The ganglia 

 lie on the lateral surfaces of the lumbar arteries near the points 

 where the latter disappear dorsally in the body-wall. The rami 

 communicantes may be found passing from the ganglia toward 

 the spinal nerve-roots. The sacral portion comprises four ganglia 

 of which the first is much larger than the others. The caudal 

 portion comprises two minute ganglia and an unpaired terminal 

 ganglion uniting the two trunks. 



