THE KIDNEYS. 



427 



much on its anterior and posterior surfaces. The kidney lies comparatively loose 

 in this fatty capsule, slipping backward and forward. The fatty capsule is continuous 

 below with the subperitoneal fat. 



Perirenal Fascia of Gerota. Covering the fatty capsule is the perirenal 

 fascia, composed of two layers anterior and posterior. The anterior is continuous 

 with that of the opposite side over the vertebral column. It proceeds outward over 

 the vessels, ureter, and kidney, and fatty capsule, blending at the outer and upper 

 border with the posterior layer ; below, it fades away in the subperitoneal tissue of 

 the iliac fossa. The posterior layer passes inward behind the kidney from its outer 

 and upper borders, to be attached to the sides of the vertebral column. Above, these 

 layers are attached to the diaphragm ; below, they are continuous with the subperi- 

 toneal tissue of the iliac fossa. There is also some perirenal fat behind the perirenal 

 fascia, between it and the muscles beneath (Fig. 436). 



Displacement of the Kidneys. The kidney is held in place by the attach- 

 ment to the diaphragm of the perirenal fascia, by its vessels, peritoneum, ureter, and 



Point of incision 



Posterior surface 



Anterior surface 



Fir,. 435. Transverse section of the kidney. The renal artery is seen dividing into anterior and posterior branches. 

 Incisions into the organ are to be made as indicated on the posterior surface just back of the prominent edge. 



by intra-abdominal pressure. Normally it cannot be felt beneath the edge of 

 the ribs. It, however, readily becomes displaced and slides down so as to be felt 

 below the costal margin; it is then called a movable kidney. If the displacement 

 becomes more marked it may descend into the iliac fossa or even toward the median 

 line; then it is called a floating or wandering kidney. In some instances it slides 

 around without pushing the peritoneum markedly forward, hence it then has no 

 mesentery or pedicle. In other cases it stretches the peritoneum in front of it and 

 has sufficient of a mesentery to allow it to come in contact with the anterior 

 abdominal wall. 



Tumors. As the kidney enlarges it does so in a forward and downward direc- 

 tion. As it comes forward it may go to the outer side of the colon, to its inner side, 

 or carry the colon directly in front 'of it. Greig Smith ("Abdominal Surgery," 

 p. 868) states that on the right side the ascending colon passes over the front and to 

 the inner side of the growth, while on the left side the descending colon passes to the 

 front and a little to the outer side. Renal tumors may be mistaken for tumors of 



