THE KIDNEYS. 637 



the rectum, in front of the pyriformis muscle, and behind 

 the pelvic fascia. Its branches are divided into internal and 

 external. The former are distributed to the pelvic viscera, 

 the latter, consisting of the greater and lesser ischiatic, glu- 

 teal, and pudic, go principally to the lower extremity. All 

 of these will be noticed in connection with the organs 

 they severally supply. 



CHAPTEK V. 



ACTIVE ORGANS OF THE TRUNK. 



FOURTH DIVISION. 

 THE ORGANS OP URINATION. 



THESE organs consist of the Kidneys, the Ureters, and 

 the Bladder. 



SECTION I. 

 THE KIDNEYS. 



The kidneys are two firm, solid bodies, situated in the 

 lumbar regions, at their, posterior portion, extending be- 

 tween the crest of the ilium and the last rib lying upon 

 the psoas magnus, quadratus lumborum, and diaphragm, 

 and corresponding to the two last dorsal, and two upper 

 lumbar vertebrae. 



Their form is that of the kidney-bean. Their size is 

 about four inches in length, and two in width. Their 

 average weight is estimated at from three to four ounces. 

 Their color is a dark, brownish red. 



The anterior surface of each kidney is convex, the right 

 having the ascending colon and duodenum upon it; the 

 left the descending colon, and both of them the peritoneum 

 upon this same surface. The posterior surface is flat. In 

 the foetus both surfaces present the lobulated appearance. 

 The outer margin is smooth and convex ; the inner presents 

 a notch, hilus renalis, where the vessels and nerves enter 

 and pass out. The upper end of each kidney is larger, 



