202 ANATOMY OF THE RABBIT. 
VII. THE ABDOMINAL AORTA, INFERIOR CAVAL VEIN, 
AND SYMPATHETIC TRUNKS. 
The dissection and removal of the intestines and urinogenital 
organs clears the dorsal body-wall for an examination of the 
abdominal portion of the aorta, the inferior cava! vein and the 
sympathetic trunks. If the inferior cava does not contain blood its 
tributaries should be cleared first, in order to keep them from being 
damaged; otherwise the branches of the aorta should first be traced. 
The anterior portion of the inferior cava has been removed with 
the liver. 
1. The abdominal portion of the aorta, described as the abdom- 
inal aorta (aorta abdominalis) extends from the hiatus aorticus 
of the diaphragm to the seventh 
lumbar vertebra, where it is 
replaced by the paired common 
iliac arteries. It passes back- 
ward in a median position along 
the ventral surfaces of the bodies 
of the vertebrae. Its natural 
continuation backwards on the 
sacrum and the caudal verte- 
brae is represented by the great- 
ly reduced median sacral artery. 
The branches of the vessel are 
distributed in two series: (1) 
Fic. 73. Plan of the pelvic bloodvessels; visceral branches (rami vis- 
Arteries: a, aorta; aei, inferior epigastric; 
Meomaolial’ ar icten Ge oeman sta (ore ae ae Ce 
aie, external iliac; ail, iliolumbar;ao,obturator; Gigestive tube and the urino- 
as, sacral; au, umbilical. Veins: vci, inferior : O 
cava; vf, femoral; vh, hypogastric; vh’, genital organs; and (2) parietal 
common hypogastric; vie, external iliac; vil; C c 
iliolumbar. branches (rami parietales) to 
the body-wall. 
The visceral branches comprise the paired renal and spermatic 
arteries, and the unpaired coeliac, superior mesenteric and 
inferior mesenteric arteries, which have already been traced. 
The parietal branches comprise: 
(a) The superior phrenic arteries (aa. phrenicae superiores), 
small vessels arising by a common trunk in the hiatus 

