j^i A MANUAL OF ANATOMY 



(ovarian in the female), and the lumbar. Excluding the lumbar 

 arteries, the order of origin of the branches is as follows : (i) inferior 

 phrenic, (2) coeliac axis, (3) superior mesenteric and (4) middle 

 capsular, both on same level, (5) renal, (6) spermatic (or ovarian), 

 (7) inferior mesenteric, and (8) middle sacral. In what follows the 

 letter P after an artery signifies parietal, and V visceral. 



The inferior phrenic arteries (P) are two in number, right and 

 left, and they are called inferior to distinguish them from the 

 superior phrenic of the internal mammary, right and left. They 

 arise, either separately or by a common trunk, from the front of the 

 aorta, whenever the vessel has passed through the aortic opening 

 of the diaphragm. They at once diverge, each passing outwards 

 and upwards over the crus of the diaphragm, the right vessel lying 

 behind the inferior vena cava, and the left behind the oesophagus. 

 Each ends by dividing into two branches, anterior and external. 

 The anterior branch passes forwards and inwards in a curved manner 

 in front of the central tendon, and anastomoses with its fellow 

 of the opposite side, and the superior phrenic and musculo-phrenic 

 of the internal mammary. The external branch passes outwards, 

 and anastomoses with the musculo-phrenic and the lower inter- 

 costal arteries. Each inferior phrenic artery furnishes a superior 

 capsular branch (or branches) to the suprarenal capsule, the right 

 vessel also giving off a few branches to the inferior vena cava, 

 whilst the left supplies a few branches to the oesophagus. 



The right inferior phrenic vein opens into the inferior vena cava, 

 and the left terminates in the left supraienal vein, left renal vein, 

 or inferior vena cava. 



The coeliac axis (V) and superior mesenteric artery (V) will be 

 found described on pp. 725, 739. 



The middle capsular arteries (V) are of small size, and are 

 two in number, right and left, each arising from the side of the 

 aorta on a level with the origin of the superior mesenteric artery. 

 The vessel passes outwards and upwards over the crus of the 

 diaphragm to the suprarenal capsule, in which it anastomoses with 

 the superior capsular of the inferior phrenic and the inferior capsular 

 of the renal. 



The right suprarenal vein opens into the inferior vena cava, and 

 the left into the left renal vein. 



The suprarenal veins originally open into the cardinal veins. The right 

 suprarenal vein becomes transferred to the upper segment of the inferior 

 vena cava (above the right renal vein). The left suprarenal vein, after the 

 obliteration of the adjacent jxirtion of the left cardinal vein, becomes trans- 

 ferred to the loft renal vein. 



The renal arteries (V) are remarkable for their large size, and 

 are two in number, right and left. They arise from the side 

 of the aorta about ^ inch lielow the superior mesenteric on a level 

 with the body of the first lumbar vertebra, the right artery being 

 usually a little lower than the left. They form right angles with 



