256 LABORATORY MANUAL FOR VERTEBRATE ANATOMY 



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

 of the liver. Follow the postcaval posteriorly carefully cleaning away conn, 

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

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

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

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

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

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

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

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

 to this vein the large right renal vein passes from the kidney into the postcav 

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

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

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

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

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

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

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

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

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

 ;aval directly, in the cat shortly posterior to the right kidney, in the rabbit mu 

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

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

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

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

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

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

 laterally along the body wall and receives an anterior branch from the neighbi 

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

 Posterior to this point the dorsal aorta comes to lie ventral to the postcav 

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

 therefore be deferred until the aorta is studied. 



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

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

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

 in R and J, page 328. 1 



Draw the postcaval and its branches as far as followed. 



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

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

 the pulmonary veins. They lie to either side of the postcaval vein, those of 1 



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

 the cat and man see Huntington and McClurc, Anatomical Record, December, 1920. 



