364 



DISSECTION OF THE ABDOMEN. 



with deep 



vessels. 



Place of 

 origin of the 

 branches ; 



their classi- 

 fication. 



Some 



visceral 



branches. 



Kenal artery 



is beneath 

 its vein ; 



gives off- 

 sets; 



difference 

 between 

 left and 

 right. 



Capsular 

 artery. 



Spermatic 

 artery is 

 remarkable : 



course to 

 the testicle 



before referred to (p. 320), but some deep vessels in connection 

 with it now come into view. As the aorta rests on the spine it lies 

 on the left lumbar veins, which end in the inferior cava. And 

 between it and the right cms of the diaphragm are the large azygos 

 vein and the thoracic duct. Along the sides of the vessel are the 

 lumbar lymphatic glands, from which large vessels run beneath it to 

 end in the beginning of the thoracic duct. 



The BRANCHES of the aorta are numerous, and arise in the following 

 order : First, are the diaphragmatic arteries, two in number, which 

 leave the front of the vessel immediately it appears in the abdomen. 

 Close to the tendinous ring of the diaphragm, the single trunk of 

 the coeliac axis arises from the front ; and about a quarter of an 

 inch lower down, also on the front, the trunk of the superior mesen- 

 teric artery begins. Half an inch lower, the renal arteries, right and 

 left, take origin from the sides of the aorta. On the lateral part of 

 the vessel, close above each renal, is the small suprarenal branch ; and 

 below the renal is the slender spermatic artery. From the front of 

 the trunk, one or two inches above the bifurcation, springs the 

 inferior mesenteric artery. And from the back of the vessel arise 

 five lumbar arteries on each side, and the middle sacral close above 

 the bifurcation. 



The branches may be classified in two sets, one to the viscera 

 of the abdomen (visceral), and another to the abdominal wall 

 (parietal). 



The visceral brandies are coeliacaxis, superior and inferior mesenteric, 

 renal, capsular. and spermatic. Of these, the first three have already 

 been examined. 



The renal arteries (fig. 138, c) leave the aorta nearly at a right 

 angle, and are directed outwards, one on each side. Near the kidney 

 each divides into four or five branches, which enter the hilum of 

 the organ between the vein and the ureter. Each artery lies 

 beneath its companion vein, being surrounded by a plexus of nerves, 

 and supplies small twigs to the suprarenal body (inferior capsular}, 

 to the ureter, and to the fatty layer about the kidney. 



The arteries of opposite sides have some differences. The left is 

 the shorter, owing to the position of the aorta : the right crosses the 

 spine, and passes beneath the vena cava. 



The middle capsular or suprareneal artery is a small branch which 

 runs almost transversely outwards to the suprareueal body from 

 the renal and diaphragmatic arteries. It is of large size in the foetus. 



The spermatic artery of the testicle (fig. 138, d) is remarkable for 

 its small size in proportion to its length, and for its leaving the 

 cavity of the abdomen. The part in the abdomen is straight, but 

 that in the cord is tortuous. 



From its origin below the renal, the vessel passes downwards 

 along the posterior wall of the abdomen to the internal abdominal 

 ring, where it enters the spermatic cord. In its course beneath the 

 peritoneum the vessel runs along the front of the psoas, crossing over 

 the ureter ; and on the right side it passes over the vena cava. It is 



