THE KIDNEY 



1243 



of the renal vessels, and, over the aorta, becomes continuous with the corresponding layer of 

 the opposite side; upward, it passes over the suprarenal gland and at the upper border of that 

 organ becomes continuous with the posterior layer; and downward, it is lost in the adipose 

 tissue intervening between the iliac fascia and muscle. The posterior layer, which is the thicker 

 of the two, passes medially behind the renal vessels and is lost in the connective tissue in front 

 of the vertebral column, and below it is lost, like the anterior layer, in the iliac region. Behind 

 the posterior layer, between it and the quadratus lumborum, is a mass of adipose tissue, the 

 pararenal adipose body, and both layers are united to the fibrous capsule of the kidney by 

 trabeculse of connective tissue which transver.se the adipose capsule. 



Each kidney is, accordingly, supported by these trabeculse in a space bounded laterally and 

 above by the layers of the renal fascia, and open medially and below. Should these trabeculse 

 become atrophied by wasting disease or ruptured by the pressure of the pregnant uterus, by 

 the improper use of corsets, or by any other cause, the phenomenon of movable or wandering 

 kidney may be set up by shght external violence, the organ tending to shift its place as far as 

 the attachment of its vessels to the main trunks and the arrangement of the renal fascia will 

 permit. 



Position and relations. — ^The kidney is said to lie in the lumbar region. It is, 

 however, intersected by the horizontal and vertical planes which separate the 

 hypochondriac, lumbar, epigastric and umbilical regions from each other, and 

 hence belongs to all these segments of the abdominal space. Its vertical level 

 may be said to correspond to the last thoracic and upper two or three lumbar 



Fig. 1006. — Section of Kidney showing the Sinus. (After Henle.) 



Cortex" 



Vessels 



'•^. 



Bottom of sinus 7^ ^ 4 



Papilla 



Two papillae surrounded by 

 a single calyx 



vertebrae, the right lying in most cases from 8 to 12 mm. (| to | in.) lower than 

 the left; but exceptions to this rule are not infrequent. 



The posterior surface (figs. 1007, 1008), with the corresponding portion of the 

 fatty capsule and the pararenal adipose body, rests against the posterior ab- 

 dominal wall extending upward in front of the eleventh and twelfth ribs, and 

 medialward to overlap the tips of the transverse processes of the first and second 

 lumbar vertebrae; the left kidney usually reaches as high as the upper border of the 

 eleventh rib, the right only to its lower border. The only visceral relation pos- 

 teriorly is on the left side, where the spleen slightly overlaps the kidnej^ opposite 

 the upper half of its lateral border, the adjacent surfaces of the two organs being, 

 however, covered by peritoneum. The parietal relations (fig. 1008) on both 

 sides are as follows: (1) the diaphragm, the left kidney, on account of its higher 

 position, entering more extensively into this relation than the right; (2) the por- 

 tion of the transversalis fascia covering the ventral surface of the quadratus 

 lumborum; (3) the lateral border of the psoas; and (4) the last thoracic, iUo- 



