ABDOMINAL CAVITY 375 



Renes. The kidneys are situated behind the peritoneum, 

 against the posterior wall of the abdomen one on each side 

 of the vertebral column. Each is enveloped by a capsule 

 of loose areolar tissue, the meshes of which are loaded with 

 soft, pliable fat. Take the fat away, and be careful to pre- 

 serve the suprarenal gland, which lies upon the upper end of 

 each kidney. 



Each kidney is placed opposite the bodies of the last thoracic 

 and the upper three lumbar vertebrae. It extends from the 

 upper border of the last thoracic vertebra to the middle of the 

 body of the third lumbar vertebra ; and it lies obliquely its 

 upper end being somewhat nearer the median plane than its 

 lower end. The kidneys lie for the most part in the hypo- 

 chondriac and epigastric regions. As a rule the left kidney 

 is confined entirely to those districts ; but the right kidney, 

 which is generally slightly lower in the abdomen than the left, 

 crosses the subcostal plane, and a small portion of its inferior 

 extremity lies in the right lumbar and the adjoining part of the 

 umbilical region. The difference between the two sides is 

 probably due to the great bulk of the right lobe of the liver. 

 On each side the twelfth rib lies behind the kidney, and the 

 right kidney does not, as a rule, extend beyond the upper 

 border of that rib, but the left kidney may reach the lower 

 border of the eleventh rib. The lower end of each kidney 

 is separated by a short but variable interval from the crest 

 of the ilium. 



The average length of a kidney is 10 cm. (four inches) its 

 breadth is about 6 cm. (two and a half inches) ; and its average 

 weight is 130 grms. (four and a half ounces) in the male, 

 but somewhat less in the female. It is a solid organ, very 

 pliable, and of a brownish-red colour. The left kidney is, as 

 a rule, slightly longer and narrower than the right kidney. 



Form of the Kidney. The form of the kidney is so char- 

 acteristic that the term "reniform," or "kidney-shaped," has 

 become common in descriptive language. The anterior sur- 

 face looks laterally and forwards, and presents impressions 

 corresponding to the viscera in contact with it ; whilst the 

 posterior surface is directed medially and backwards, and is 

 moulded accurately upon the parts which support it. The 

 extremities are rounded, and the superior end is usually thicker 

 and more massive than the inferior. The lateral border^ 

 smooth and convex, is directed backwards and laterally; 



