

678 ANGIOLOGY 



the front of the vertebral column, on the right side of the aorta, and, having reached 

 the liver, is continued in a groove on its posterior surface. It then perforates 

 the diaphragm between the median and right portions of its central tendon; 

 it subsequently inclines forward and medialward for about 2.5 cm., and, piercing 

 the fibrous pericardium, passes behind the serous pericardium to open into the 

 lower and back part of the right atrium. In front of its atrial orifice is a semilunar 

 valve, termed the valve of the inferior vena cava : this is rudimentary in the adult, 

 but is of large size and exercises an important function in the fetus (see page 540). 



Relations. The abdominal portion of the inferior vena cava is in relation in front, from below 

 upward, with the right common iliac artery, the mesentery, the right internal spermatic artery, 

 the inferior part of the duodenum, the pancreas, the common bile duct, the portal vein, and the 

 posterior surface of the liver; the last partly overlaps and occasionally completely surrounds it; 

 behind, with the vertebral column, the right Psoas major, the right crus of the diaphragm, the 

 right inferior phrenic, suprarenal, renal and lumbar arteries, right sympathetic trunk and right 

 celiac ganglion, and the medial part of the right suprarenal gland; on the right side, with the 

 right kidney and ureter; on the left side, with the aorta, right crus of the diaphragm, and the 

 caudate lobe of the liver. 



The thoracic portion is only about 2.5 cm. in length, and is situated partly inside and partly 

 outside the pericardial sac. The extrapericardial part is separated from the right pleura and 

 lung by a fibrous band, named the right phrenicopericardiac ligament. This ligament, often 

 feebly marked, is attached below to the margin of the vena-caval opening in the diaphragm, and 

 above to the pericardium in front of and behind the root of the right lung. The intrapericardiac 

 part is very short, and is covered antero-laterally by the serous layer of the pericardium. 



Peculiarities. In Position. This vessel is sometimes placed on the left side of the aorta, 

 as high as the left renal vein, and, after receiving this vein, crosses over to its usual position on 

 the right side; or it may be placed altogether on the left side of the aorta, and in such a case the 

 abdominal and thoracic viscera, together with the great vessels, are all transposed. 



Point of Termination. Occasionally the inferior vena cava joins the azygos vein, which is 

 then of large size. In such cases, the superior vena cava receives the whole of the blood from 

 the body before transmitting it to the right atrium, except the blood from the hepatic veins, 

 which passes directly into the right atrium. 



Tributaries. The inferior vena cava receives the following veins: 



Lumbar. Renal. Inferior Phrenic. 



Right Spermatic or Ovarian. Suprarenal. Hepatic. 



The Lumbar Veins (w. lumbales) four in number on each side, collect the blood 

 by dorsal tributaries from the muscles and integument of the loins, and by abdomi- 

 nal tributaries from the walls of the abdomen, where they communicate with the 

 epigastric veins. At the vertebral column, they receive veins from the vertebral 

 plexuses, and then pass forward, around the sides of the bodies of the vertebrae, 

 beneath the Psoas major, and end in the back part of the inferior cava. The left 

 lumbar veins are longer than the right, and pass behind the aorta. The lumbar 

 veins are connected together by a longitudinal vein which passes in front of the 

 transverse processes of the lumbar vertebrae, and is called the ascending lumbar; 

 it forms the most frequent origin of the corresponding azygos or hemiazygos vein, 

 and serves to connect the common iliac, iliolumbar, and azygos or hemiazygos 

 veins of its own side of the body. 



The Spermatic Veins (w. spermaticce) (Fig. 590) emerge from the back of the 

 testis, and receive tributaries from the epididymis; they unite and form a convo- 

 luted plexus, called the pampiniform plexus, which constitutes the greater mass of 

 the spermatic cord; the vessels composing this plexus are very numerous, and 

 ascend along the cord, in front of the ductus deferens. Below the subcutaneous 

 inguinal ring they unite to form three or four veins, which pass along the inguinal 

 canal, and, entering the abdomen through the abdominal inguinal ring, coalesce 

 to form two veins, which ascend on the Psoas major, behind the peritoneum, lying 

 one on either side of the internal spermatic artery. These unite to form a single 

 vein, which opens on the right side into the inferior vena cava, at an acute angle; 

 on the left side into the left renal vein, at a right angle. The spermatic veins 



