256 LABORATORY MANUAL FOR VERTEBRATE ANATOMY 



liver into the postcaval vein. These are best seen by dissecting in the substance 

 of the liver. Follow the postcaval posteriorly carefully cleaning away connec- 

 tive tissue and fat from it and its tributaries. It runs slightly to the right of 

 the mid-dorsal line of the peritoneal cavity alongside the dorsal aorta which 

 must not be injured. The first tributary of the postcaval is the right adreno- 

 lumbar vein. This passes along the posterior surface of a small gland, the adrenal 

 gland, which lies anterior to the kidney in contact with the postcaval vein and 

 will be found by dissecting in the fat in this location. The adrenolumbar vein 

 receives branches for the adrenal gland (which is one of the glands of internal 

 secretion) and also collects from the adjacent body wall. Immediately posterior 

 to this vein the large right renal vein passes from the kidney into the postcaval. 

 Next, by turning the viscera to the right locate the left adrenal gland and kidney 

 and find the left adrenolumbar and renal veins. They are situated posterior to 

 the right ones. The left adrenolumbar and renal veins generally unite to a 

 common stem before they enter the postcaval. Into the left renal vein opens 

 the vein of the left gonad. In male specimens this is the left internal spermatic 

 vein; it may be traced posteriorly (in contact with the postcaval in the rabbit) 

 to the scrotum. In female specimens it is the left ovarian vein which comes from 

 the ovary, a small oval body lying about the middle of the lateral wall of the 

 peritoneal cavity. The right internal spermatic or ovarian vein enters the post- 

 caval directly, in the cat shortly posterior to the right kidney, in the rabbit much 

 farther caudad The postcaval vein in its course along the body wall receives 

 at regular intervals the paired lumbar veins from the wall; these are seen by 

 loosening the vein, raising it slightly, and looking on its dorsal surface. The 

 lumbar veins are then seen passing ventrally in the median groove between muscle 

 masses. Near the posterior end of the peritoneal cavity the postcaval receives 

 a pair of iliolumbar veins. Each of these in company with an artery extends 

 laterally along the body wall and receives an anterior branch from the neighbor- 

 hood of the kidney. Sometimes the left ovarian vein enters the left iliolumbar. 

 Posterior to this point the dorsal aorta comes to lie ventral to the postcaval, 

 concealing the latter. The dissection of the remainder of the postcaval will 

 therefore be deferred until the aorta is studied. 



It is very common for the postcaval and its branches to vary considerably 

 from the foregoing account. An apparent splitting of the postcaval into two 

 main trunks posterior to the kidneys is a common variation; others are mentioned 

 in R and J, page 328.' 



Draw the postcaval and its branches as far as followed. 



4. The pulmonary veins. Examine the roots of the lungs and note numerous 

 veins, several on each side, entering the left auricle from the lungs. These are 

 the pulmonary veins. They lie to either side of the postcaval vein, those of the 



1 For a more detailed account of the occurrence and origin of these variations of the postcaval in 

 the cat and man see Huntington and McClure. Anatomical Record, December, iQ2o. 



