134 Anatomy of the Rabbit. 



(a) The external iliac artery (a. iliaca externa) is the larger 

 lateral branch, directed toward the inguinal ligament, over 

 which it passes to the medial surface of the limb as the 

 femoral artery. It gives off the inferior epigastric artery 

 (a. epigastrica inferior), which passes forward on the medial 

 portion of the abdominal wall (see note p. 115). 



(b) The hypogastric artery (a. hypogastrica) is the smaller medial 

 branch, directed backward on the dorsal wall of the pelvis. 

 At its junction with the external iliac the vessel gives off the 

 umbilical artery (a. umbilicalis) to the bladder, or in the 

 female first to the vagina and uterus (a. uterina). The 

 obturator artery (a. obturatoria) passes laterad to the pelvic 

 wall, and the middle haemorrhoidal (see note p. 130) to the 

 side of the rectum. The main vessel leaves the pelvic cavity, 

 passing to the lateral side of the abductor caudae anterior, 

 and reappears posteriorly as the internal pudendal (note 

 p. 130). The intermediate branches pass to the posterior 

 limb and the side of the tail (p. 149). 



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, and 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. 121). 

 Its parietal tributaries (radices parietales) include the inferior phrenic 

 veins (vv. 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 s_ympathicus) . Its lumbar, 

 sacral, and 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 two are much 

 larger than the others. The caudal portion comprises two minute 

 ganglia and an unpaired terminal ganglion uniting the two trunks. 



