422 CLINICAL APPLIED ANATOMY. 



Injuries to the Kidney. The kidney being retroperitoneal, 

 it is possible for it to be extensively lacerated as the result of 

 blows, falls and other injuries, without the peritoneum being 

 involved. Being supported by the bodies and transverse pro- 

 cesses of vertebrae, and also by the last rib, it may be crushed 

 against these bony points by violence applied in front. The 

 impressions left in a hardened kidney by the twelfth rib and 

 transverse processes of the first and second lumbar vertebrae 

 show how intimate the relation is. If the proper capsule of the 

 kidney is torn, the extravasated blood is mainly checked by the 

 renal fascia which forms the outer boundary of the fatty capsule ; 

 if the blood escapes through this, there is but little obstacle to 

 its wide dissemination in the connective tissue planes of the 

 abdominal wall. Extravasated urine is usually present, as well 

 as blood, and may be in large quantity if the renal pelvis is 

 torn. Haematuria often occurs. Kents of the peritoneal covering 

 when present add much to the gravity of the condition. 



In acute flexion of the spine the kidney may be squeezed 

 between the ilium and the lower ribs. 



The kidney may be injured from behind by a penetrating 

 wound without implication of the peritoneum, but this is very 

 unlikely when the wound penetrates from in front. 



Perinephritic abscess is situated in the retroperitoneal tissue 

 in which the kidney lies, and must be distinguished from localised 

 intraperitoneal suppuration in front of the kidney. Perine- 

 phritic abscesses may be primary, such as occur from injury 

 or during the course of certain infectious diseases, or may arise 

 by extension of suppuration in the neighbourhood. The infec- 

 tion may extend from a lesion of the kidney, such as calculus, 

 tuberculosis, or abscess, or may originate in the bones of the 

 spine, or arise in connexion with the vermiform appendix, 

 colon, pancreas, or duodenum. In the case of the vermiform 

 appendix, the peritoneum will have been perforated in some 

 manner ; but with extension from the colon, pancreas and duo- 

 denum, this is not essential, since all these have areas free from 

 the serous membrane. Sometimes perinephritic infection spreads 



