506 LABORATORY MANUAL OF HUMAN ANATOMY 



Kidney (Ren). (Vide Fig. 271, and Spalteholz, Figs. 634-636.) 



Study the exact relation of the kidneys to the vertebrae, the 

 psoas and quadratus lumborum muscles, the twelfth rib, and 

 the crest of the ilium. Which kidney is the lower ! How do you 

 account for this low position? Note the relation of the right 

 kidney to the liver, the duodenum, and the flexura coli dextra, 

 and the relation of the left kidney to the pancreas, the stomach, 

 the spleen, and the flexura coli sinistra. 



Direction and Orientation. 



The kidney is not vertically placed. Its axis is directed obliquely 

 downward and lateralward. The superior extremity approaches the 

 median line. The anterior surface is directed lateralward and the pos- 

 terior medialward. 



Perirenal Fascia. (Figs. 268 and 269. ) l 



(a) Eetrorenal layer. 



This layer of fascia is found between the posterior surface of 

 the kidney and the aponeurosis of the quadratus lumborum 

 muscle. It covers the sheath of the psoas muscle, reinforcing it, 

 and is attached to the vertebrae and intervertebral disks, medial 

 to the attachment of the psoas. It does not become continuous 

 with the corresponding fascia of the opposite side. 



(b) Prerenal fascia. 



This layer of fascia follows closely the reflections of the peri- 

 toneum about the kidneys. It passes in front of each kidney 

 and its corresponding pedicle, the aorta and inferior vena cava, 

 to become continuous with the corresponding fascia of the oppo- 

 site side. 



If these two fasciae are traced longitudinally, they will be 

 found to fuse above and become attached to the diaphragm. 

 Below, fusion does not occur; the anterior layer follows the 

 reflections of the peritoneum, while the posterior layer divides 

 into several lamellae which fuse with the cellular tissue of the 

 iliac fossa. 



Vessels of the Kidney. 



In injected specimens study 



Arteries of Kidney (Arteriae renales). 



(a) Interlobar arteries of kidney (Aa. interlobares renis). 



(aa) Arciform arteries or renal arches (Aa. arci formes) . 



(ab) Interlobular arteries (Aa. interlobulares) . 



1 For a description of the perineal fascia, consult " The Present Conception 

 of the Perineal Fascia and its Role in Fixation of the Kidney," by D. D. 

 Lewis, in Jour. Amer. Med. Assoc., vol. xlii. p. 701. 



