THE BACK. 1439 



The upper part of the ureter is exposed by extending the division of the 

 abdominal muscles still further downwards and forwards into the iliac region. 

 After stripping the peritoneum off the quadratus and psoas muscles, the ureter 

 will be found to cling to the deep surface of the membrane. Care is taken not 

 to injure the internal spermatic or ovarian vessels, which cross the ureter super- 

 ficially, and from the medial to the lateral side. The ureter is surrounded by a 

 quantity of loose cellular tissue, and, owing to an abundance of elastic fibres in its 

 adventitious coat, is very elastic, so that it can be readily pulled up to the surface. 



To deliver an enlarged kidney out of the loin, it is generally necessary to 

 prolong the incision upwards so as to divide the lateral lumbo-costal arch ; and 

 it may be necessary to divide, fracture, or resect the twelfth rib also. In doing 

 this it is not always possible to avoid opening into the lowest part of the pleural 

 sinus, which descends in front of the medial half of the rib. 



In operating on the kidney, the last thoracic, and the ilio-hypogastric and 

 ilio-inguinal nerves, which lie between it and the quadratus lumborum, must not 

 be injured ; the last thoracic nerve should be retracted upwards and laterally, 

 the other two downwards and medially. 



A needle passed through the medial extremity of the eleventh intercostal 

 space will transfix the suprarenal gland. 



The pus of a perinephric abscess occupies the fatty layer of the tela subserosa 

 (perinephric fat), and lies, therefore, within the fascial envelope of the abdomen ; 

 the pus in a psoas abscess, on the other hand, lies external to the fascia. In 

 opening a psoas abscess from behind, a vertical incision is made in the angle 

 formed by the lateral border of the sacrospinalis and the crest of the ilium ; in 

 the deeper part of the dissection the surgeon should keep close to the front of 

 the transverse process of the fourth lumbar vertebra. 



Diaphragm, Liver, Stomach, and Large Intestine. Posteriorly the right 

 arch of the diaphragm and the right lobe of the liver extend upwards to the level 

 of the angle of the scapula (eighth rib), while the left arch and the fundus of the 

 stomach lie one inch lower (eighth interspace) ; the central tendon reaches up to 

 the eighth thoracic spine. The right lobe of the liver is covered posteriorly by 

 the eighth to the twelfth ribs, and is overlapped by the base of the right lung as 

 far as a line drawn horizontally laterally from the tenth thoracic spine; hence, 

 posteriorly, the superior limit of the liver cannot be defined by percussion, and its 

 inferior limit merges into the dulness of the loin muscles and kidney. 



The cardiac orifice of the stomach lies one inch to the left of the ninth thoracic 

 spine. The cardiac portion, overlapped by the ninth to the twelfth ribs, extends 

 upwards to the level of the eighth thoracic spine, one inch below the inferior 

 angle of the scapula. The pyloric portion crosses the median plane opposite the 

 first and second lumbar spines, the pylorus itself being situated one inch to the 

 right of the first lumbar spine. The lesser curvature lies to the left of and below 

 the tenth, eleventh, and twelfth thoracic spines. 



Viewed from behind, the large intestine, on both sides, overlaps the lateral 



border of the kidneys and lies parallel to the lateral border of the sacrospinalis 



muscles. The peritoneum is reflected from the colon on to the posterior abdominal 



wall along a line drawn vertically upwards from the centre of the iliac crest. The 



left flexure of the colon, which reaches up to the level of the twelfth thoracic spine 



i and the tenth rib, lies about five inches above the iliac crest. The right flexure 



. lies on a level with the first lumbar spine. 



Spleen. The spleen, situated in the left hypochondrium, behind the cardiac end 

 of the stomach, is overlapped by the ninth, tenth, and eleventh ribs, the long axis 

 of the organ corresponding approximately to that of the tenth rib. Between the 

 :: superior third of the spleen and the chest wall (pleura and diaphragm intervening) 

 i is the base of the left lung, the inferior margin of which crosses the organ horizont- 

 ally at the level of the tenth thoracic spine. The costo-diaphragmatic reflection of 

 : the pleura reaches down as far as the inferior angle of the spleen. The superior 

 limit of the organ cannot therefore be defined by percussion ; and unless enlarged, 

 or displaced downwards, the spleen cannot be punctured from behind without travers- 

 ing the pleural as well as the peritoneal cavity. 



