290 SURGICAL APPLIED ANATOMY. [Chap. xvi. 



of injury) come through the fascia lumborum and 

 internal oblique muscles, since those structures form the 

 floor of the triangle. Diaphragmatic hernice may be 

 congenital or acquired. The former variety is by far 

 the more common, and is due to simple arrest in the 

 development of the diaphragm and persistence of the 

 original connection between the thorax and abdomen. 

 The acquired form usually follows a laceration of the 

 diaphragm from injury. In any case some of the 

 abdominal viscera are protruded, through the gap in 

 the midriff, into the thoracic cavity. Owing to the 

 presence of the liver on the right side, these hernias 

 are much more common on the left side. Of the 

 organs, the stomach is the most frequently dislodged, 

 then the transverse colon, omentum, small gut, spleen, 

 liver, pancreas, and kidneys in the order named (Leich- 

 tenstern). The hernia may escape through the foramen 

 for the gullet, but never through that for the vena 

 cava, nor through the hiatus aorticus. The parts 

 commonly selected are the connective tissue intervals 

 between the sternal and costal origins of the diaphragm 

 in front and its vertebral and costal origins behind. 

 These hernise are more common in males. 



Posterior abdominal parietes. The lateral 

 and posterior walls of the abdomen are lined inside with 

 two fascia?, the trans versalis and iliac. Thetransversalis 

 fascia lines the whole of the transversalis muscle, and is 

 much thicker below than above. Above it joins the 

 fascia covering the diaphragm, while below it is at- 

 tached to the iliac crest, and to the whole of Poupart's 

 ligament, save at that spot where it passes into the 

 thigh to form the anterior layer of the crural sheath. 

 The iliac fascia encloses the ilio-psoas muscle, the part 

 over the psoas being the thinner. This part is attached 

 on the inner side to the sacrum, and to the spine at 

 points corresponding to the psoas origin. Above, it is 

 attached to the ligamentum arcuatum internum, and 



