TRIBUTARIES OF THE INFERIOR VENA CAVA. 535 



2. The spermatic veins (in the male) proceed upwards from the testicle and 

 epididymis, and form in the spermatic cord a thick plexus of convoluted vessels 

 known as the spermatic or pampiniform plexus. Passing through the inguinal canal 

 into the abdomen, in company with the spermatic artery, the branches from this 

 plexus join into two or three veins, and these again unite into a single vessel which 

 ascends beneath the peritoneum, on the surface of the psoas muscle, and opens on 

 the right side into the vena cava, on the left into the renal vein. The spermatic 

 veins sometimes bifurcate before their termination, and in this case one branch may 

 enter the vena cava, the other the renal vein. 



The spermatic veins receive small branches from the ureter and th? abdominal 

 wall ; and the left, which is usually larger than the right, is joined also by one or 

 two colico-spermatw veins from the descending colon. 1 



In the female the ovarian veins have the same general course as the ovarian 

 arteries ; they form a plexus near the ovary (ovarian or pampiniform plexus) in the 

 broad ligament, and communicate freely with the uterine plexus. 



Valves are often present in the spermatic veins, especially in the pampiniform 

 plexus ; and in exceptional cases they have been seen in the ovarian veins. There 

 is also in most cases a valve at the termination of each spermatic or ovarian vein ; 

 but this is not unfrequently absent on the left side, and then a valve will generally 

 be found in the renal vein not more than a quarter of an inch from the entrance of 

 the former vessel (Rivington). 



3. The renal or emulgent veins are short but wide vessels which issue from 

 the hihim of the kidney, and pass inwards in front of the corresponding arteries to 

 join the vena cava nearly at a right angle, the left usually a little higher up than 

 the right. The vein of the left side is also longer than the right, and passes in 

 front of (rarely behind) the aorta. The renal veins receive small branches from the 

 suprarenal bodies, and the left is joined also by the spermatic and capsular veins of 

 the same side. Yalves are occasionally present in the renal veins or in some of 

 their branches. 



4. The capsular or suprarenal veins are, relatively to the organs from which 

 they arise, of considerable size. On the right side the vein ends in the vena cava, 

 on the left in the renal vein. 



5. The hepatic veins return the blood conveyed to the liver by the portal vein 

 and the hepatic artery. They converge to the groove in which the inferior vena 

 cava lies, and are collected mainly into two or three large trunks which open 

 obliquely into that vessel. There is also a variable number of smaller branches 

 which collect the blood from the adjacent portions of the gland and pass directly 

 into the vena cava. The hepatic veins have no valves ; but, owing to their oblique 

 entrance into the vena cava, a semilunar fold is formed at the lower border of the 

 orifice of each vein. 



6. The inferior phrenic veins are two in number on each side, and follow the 

 course of the arteries of the same name. On the left side these veins often join the 

 suprarenal vein. 



Varieties. It occasionally happens that the left common iliac vein is continued upwards 

 on the left side of the aorta, after having given off, in most of these cases, a connecting 

 branch of variable size to the right vein at the usual place of junction. About the level of 

 the second lumbar vertebra it receives the left renal vein, and then crosses in front of (very 

 rarely behind) the aorta to join the right common iliac vein, which passes up in the usual 

 place of the inferior vena cava. The vein on the left of the aorta in these cases is probably 

 a persistent lower portion of the left cardinal vein of the foetus. In rarer cases the inferior 

 vena cava is placed in the lower part of its course on the left side of the aorta, and crosses 

 over the latter vessel to gain its usual situation, after having been joined by the left renal 



1 W. H. Bennett, " On Varicocele," 1891. This work may be consulted for additional details as to 

 the disposition of the spermatic veins. 



