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. 



I . 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: (i) 

 visceral branches (rami vis- 

 cerales) to the parts of the 

 digestive tube and the urino- 

 genital organs ; and (2) parietal 

 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 



Fig. 73. Plan of the pelvic bloodvessels; 

 Arteries: a, aorta; aei, inferior epigastric; 

 af, femoral; ah, hypogastric; ahm, middle 

 haemorrhoidal; al, sciatic; aic, common iliac ; 

 aie, external iliac; ail, iliolumbar; ao, obturator; 

 as, sacral; au, umbilical. Veins: vci, inferior 

 cava; vf, femoral; vh, hypogastric; vh', 

 common hypogastric; vie, external iliac; vil; 

 iliolumbar. 



