

VISCEEAL BKANCHES OF THE ABDOMINAL AOETA. 927 



4. The vas aberrans is a variable and inconstant branch of the thoracic aorta ; 

 it represents the dorsal roots of the fourth and sixth right aortic arches of the 

 embryo. When present it arises from the front and right side of the upper part of 

 the descending aorta near the upper left bronchial artery, and passes upwards and 

 to the right behind the oesophagus ; it frequently anastomoses with the right 

 superior intercostal artery, and it may be enlarged and form the first part of 

 the right subclavian artery. 



BRANCHES OF THE ABDOMINAL AORTA. 



The branches of the abdominal portion of the aorta are distributed almost 

 entirely to the walls and contents of the abdominal cavity, but some supply 

 small branches to the vertebral column, and to the contents of the vertebral canal, 

 and others are prolonged into the pelvis minor. They are divisible into visceral 

 and parietal groups, both of which include paired and single (unpaired) vessels. 



( Suprarenal. 

 Paired, j Renal. f f Inferior phrenic. 



Visceral. 

 T, 



v Spermatic or ovarian. p . . , I Paired.^ Lumbar. 



j Coeliac axis. *1 [Common iliac. 



Single, -j Superior mesenteric. [ Single. Middle sacral, 

 [inferior mesenteric. 



THE PAIRED VISCERAL BRANCHES OF THE ABDOMINAL AORTA. 



1. Arterise Suprarenales (Fig. 773). There are three pairs of suprarenal 

 arteries the superior, middle, and inferior. Of these the middle only arise 

 directly from the aorta ; the superior spring from the inferior phrenic, and the 

 inferior from the renal arteries. 



The middle suprarenal arteries are two small branches which arise, posterior to 

 the pancreas, from the sides of the aorta, close to the origin of the superior mesen- 

 teric artery. They run, one on each side, laterally and upwards, upon the crura of 

 the diaphragm just above the renal arteries, to the suprarenal glands, to which they 

 are distributed. They anastomose with the superior and inferior suprarenal arteries. 



2. Arterise Renales. The renal arteries (Fig. V73) arise, one on each side, 

 from the aorta, about 12 mm. (half an inch) below the origin of the superior 

 mesenteric artery and opposite the second lumbar vertebra. 



Both arteries are of large size, and the right is frequently slightly lower in 

 position than the left. Each artery runs almost transversely to the hilum of the 

 corresponding kidney. It passes anterior to the crus of the diaphragm and the 

 upper part of the psoas muscle. The left artery lies posterior to the pancreas; 

 the right vessel passes behind the inferior vena cava, the head of the pancreas, 

 and the descending part of the duodenum. The renal vein usually lies below and 

 anterior to the artery, but near the kidney the vein not infrequently occupies a 

 posterior position. 



On reaching the hilum of the kidney each artery divides into three branches, 

 two of which pass anterior to the pelvis renalis, and between it and the renal 

 vein, and the third posterior to the pelvis. In the renal sinus these primary 

 branches break up into numerous secondary branches which enter the kidney 

 substance between the pyramids. 



Branches. The following branches are given off by each renal artery, in addition to the 

 terminal branches : 



Inferior suprarenal, which passes upwards to the lower part of the suprarenal gland. 

 TJreteral. Small branches to the upper part of the ureter, which anastomose with branches 

 the internal spermatic or ovarian arteries. 



(c) Peri-nephric. Small branches to the fatty capsule of the kidney, which anastomose with 

 tie lumbar arteries. 



(d) Glandular offsets, either from the main trunk or from some of its branches, pass to the 



lymph glands. 



lum 



in 



. Arterise Spermaticse Internae. The Internal spermatic arteries are present 

 in both sexes; in the male they are called the testicular arteries and in the 



