182 ANATOMY OF TUB ABDOMEN, ETC. 



They arise from the posterior aspect of the aorta, those of 

 the right side being the longest and covered in by the vena 

 cava ; passing over the bodies of the vertebrae they dip 

 beneath the psoas muscle and divide into two branches, 

 one of which goes to the spinal cord and spinal muscles, 

 while the other continues its course forward to the abdo- 

 minal muscles. The first lumbar artery passes under the 

 pillar of the diaphragm, and along the edge of the last 

 rib ; the last lumbar passes along the crest of the ilium. 

 The lumbar arteries of the opposite sides sometimes arise 

 by a common trunk, which sends out its branches laterally ; 

 two arteries of the same side are sometimes conjoined at 

 their origin. 



The EXTERNAL ILIAC YEIN is the continuation of the 

 femoral vein, and will be found accompanying the external 

 iliac artery ; at Poupart's ligament it lies on the inside of 

 the artery, but gradually get.s beneath it ; it is joined by 

 the internal iliac vein, which returns the blood from the 

 penis and pelvic viscera. These two veins form the com- 

 mon iliac veins, which, uniting upon the right side of the 

 aorta, form the VENA CAVA INFERIOR ; this ascends along 

 the right side of the abdominal aorta, receiving in its course 

 the lumbar veins, which accompany the.lumbar arteries, the 

 left being the longest ; the renal, which lie in front of the 

 renal arteries, the left renal crossing the aorta and being 

 the longest; the supra-renal, which, however, sometimes 

 terminate in the renal ; the phrenic, returning the blood 

 from .the diaphragm, and the hepatic, which empties the 

 blood from the portal system and the hepatic artery. The 

 phrenic and hepatic veins cannot be seen until the liver is 

 removed. The spermatic veins are long and slender veins 

 accompanying the spermatic arteries ; the right spermatic 

 enters the front of the vena cava, the left spermatic enters 

 the left renal vein ; these return the blood from the scrotum 

 and testicles. The vena cava passes out of sight beneath 

 the liver, where it traverses a groove in that organ destined 

 for it, and passing through a special opening in the dia- 

 phragm, penetrates the pericardium and terminates in the 

 right auricle of the heart. The vena azygos major and 

 minor (p. 123), originate from the lumbar veins, and pass 

 up beneath the diaphragm to unite with the vena cava 

 superior. 



