274 . URINARY SYSTEM. 



Relative Situation and Attachment. — In consequence of the 

 kidneys not receiving the same complete covering from the peri- 

 toneum as the abdominal viscera in general*, they have been 

 regarded as extra abdominal organs ; custom, however, appears 

 to be somewhat capricious in this particular, for they are cer- 

 tainly as much within the cavity as the pancreas* (which, no 

 more' than the kidneys, gets but a covering on one side from the 

 peritoneum), and may, anatomically considered, with equal pro- 

 priety, be included among the viscera of the abdomen. Indeed, 

 they cannot be properly examined in situ but from within the 

 abdominal cavity. Herein they are found a little further back- 

 ward than the pancreas, immediately above (or concealed by, as 

 the horse lies upon his back) the small intestines. They repose, 

 one upon either side of the spine, close to the bodies of the 

 lumbar vertebrae, or rather underneath the psose muscles, to 

 which they are firmly attached by a surrounding and enveloping 

 mass of adipose and cellular substance, as well as to the vertebrse 

 themselves. Their anterior ends reach under the last ribs ; 

 posteriorly they come in contact with the cristse of the ilea ; 

 and to both these parts they are tied by cellular tissue. 

 They receive some support from the peritoneum as it passes 

 under them, and are attached by it to the contiguous viscera ; 

 but their strongest connexion is to the spine through the me- 

 dium of their bloodvessels. The right kidney has peritoneal 

 attachments to the right lobe of the liver, and to the head of the 

 pancreas : the left has a similar connexion with the blind pouch 

 of the stomach, from the pressure of which in a state of dis- 

 tention it is pushed a little further backward than the right; the 

 left is also connected with the pancreas and the spleen. 



Figure. — The figure of the kidney varies remarkably in dif- 

 ferent subjects; nay, the right is commonly unlike the left, is 

 less elongated and broader : in fact, it is a gland that does not 

 appear to possess any very determinate form. Generally speak- 

 ing, it may be said to represent an irregular flattened oval : but 

 it is an imperfect oval ; one side is interrupted by an inlet or 

 deficiency of substance, technically called the notch, into which 

 the bloodvessels are received. 



Magnitude. — The magnitude of the gland, not less unde- 

 terminable than its form, estimated by its weight, may be stated 

 in round numbers to average about forty ounces. 



Division. — The kidney may be divided into its upper and 

 under surfaces, its border, and its notch. The under surface, 

 the part covered by peritoneum (underneath which is interposed 



* Vide " Reflection of Peritoneum," page 249. 



