744 A MANUAL OF ANATOMY 



(i) the stomach, (2) the small and large intestine, except a portion 

 of the anal canal, (3) the pancreas, (4) the spleen, and (5) the gall- 

 bladder. 



Summary of the Tributaries of the Vena Portse. — (i) The superior mesenteric 

 vein, which takes up (o) the right gastro-epiploic, (b) the pancreatico-duodenal, 

 (c) the rami intestini tenuis, (d) the ileo-colic, (e) the right colic, and (/) the 

 middle colic. (2) The splenic vein, which takes up {a) the gastric vasa brevia, 

 (6) the left gastro-epiploic, (c) many pancreatic veins, and (d) the inferior 

 mesenteric (as a rule), which in turn takes up the superior hemorrhoidal, 

 sigmoid, and left colic veins. (3) The pyloric vein. (4) The gastric vein. 

 (S) The cystic vein. 



The portal vein and its tributaries are destitute of valves, so 

 that the blood can regurgitate in cases of portal obstruction. 



Development of the Vena Portse. — The lower portion of the vein results 

 from the union of the two vitelline veins. The upper portion is developed 

 from the left half of the lower venous ring and the right half of the upper 

 venous ring, formed by the vitelline veins around the primitive duodenum. 



For a description of the common bile-duct, see p. 710, 

 Kidneys. — ^The kidneys are two in number, right and left, and are 

 situated deeply at the posterior part of the abdomen, where they 

 lie behind the peritoneum. They chiefly occupy portions of the 

 epigastric and hypochondriac regions, but also extend slightly 

 into the umbilical and lumbar regions. Relatively to the vertebral 

 column they extend from the level of the upper border of the last 

 thoracic vertebra to about the centre of the body of the third 

 lumbar, the right kidney being usually somewhat lower than the 

 left. The long axis of each organ is directed downwards and slightly 

 outwards, so that their upper ends are rather nearer the middle line 

 than the lower. The superior limit of the right kidney is usually the 

 lower border of the eleventh rib, whilst that of the left is usually 

 the upper border of the eleventh rib. Inferiorly the organs ap- 

 proach the iliac crests, from which they are distant about 2 inches, 

 the right being the nearer of the two. Each kidney is surrounded 

 by a quantity of areolar and adipose tissues, constituting the adipose 

 capsule, which, along with the adjacent viscera, anchors the organ. 

 The length of a kidney is about 4 inches, the breadth about 2^ inches, 

 and the thickness about i|^ inches. The right kidney is usually shorter 

 and broader than the left. The weight of the organ is about 5J 

 ounces. In form the kidney is bean-shaped. It presents two smooth 

 surfaces, two extremities, and two borders. The anterior surface 

 looks outwards as well as forwards, and presents important visceral 

 impressions, whilst the posterior surface looks inwards as well as 

 backwards, and presents muscular impressions. The extremities 

 are enlarged and round, the superior more so than the inferior, the 

 latter often assuming a somewhat pointed appearance. The 

 external border has an inclination backwards, and is convex and 

 free. The internal border has an inclination forwards, is concave, 

 and is connected with the renal vessels and the pelvis of the kidney. 



