Chap, xvii.] THE ABDOMINAL VISCERA. 295 



Between the last rib and the iliac crest is stretched 

 the dense fascia lurnborum, the posterior aponeurosis 

 of the trans versalis muscle. It is pierced near the rib 

 by the last intercostal artery and nerve and near the 

 ilium by the ilio-hypogastric nerve and its accompany- 

 ing artery. It is along these structures that an abscess 

 may possibly find its way through the fascia in certain 

 cases. The fascia divides behind into three layers, to 

 enclose in definite spaces the quadratus and erector 

 spinse muscles. Within these spaces or compartments 

 suppuration may be for some time limited. A lumbar 

 abscess commencing in some adjacent part, as in the 

 spine or in the loose tissue around the kidneys, 

 usually spreads backwards by piercing the fascia 

 lumborum or the quadratus muscle. It then finds its 

 way through the internal oblique, and appears on the 

 surface between the external oblique and latissimus 

 dorsi muscles, and at the outer border of the erector 

 spinse. It should be noted that the quadratus muscle 

 is very thin, and offers little resistance to protrusions 

 from within, while a great part of the muscle is firmly 

 supported behind by the erector spirise. 



CHAPTER XVII. 



THE ABDOMINAL VISCERA. 



THE peritoneum. Certain of the viscera, as, 

 for example, the stomach, spleen, and small intestines, 

 are so closely invested with peritoneum that they could 

 not be wounded without that membrane being wounded 

 also. Inflammatory affections of such viscera are also 

 very apt to involve the peritoneum. Other organs, 

 such as the kidney, descending colon, pancreas, etc., 



