The Inguinal Region . 187 



form fascia and the subserous areolar tissue, and, lastly, (6) 

 the peritoneum. If we examine the internal or abdominal as- 

 pect of the inguinal region, we see, two, and sometimes 

 three, ridges converging towards the umbilicus. These are 

 caused by the urachus, the deep epigastric artery and the 

 remains of the obliterated hypogastric vessel. The for- 

 mer lies in the middle line, whereas, the latter two, fre- 

 quently run together producing one elevation only. If, 

 however, each pursues an independent course, there result, 

 in addition to the ridge formed by the urachus, two pro- 

 jections. These ridges are caused by the above structures 

 raising up or elevating the peritoneum over them, since 

 they lie between the peritoneum and the transversalis fas- 

 cia. 



These elevations necessitate corresponding depressions, 

 and, of the latter, there may be two or three. If two exist, 

 one is external to the deep epigastric and the other is 

 internal to it. If three ridges be present, there are three 

 corresponding depressions, or, fossae, viz., one external to 

 the epigastric, one between it and the remains of the hypo- 

 gastric, and a third between the latter and the urachus. 



Hernia. The inguinal region is quite frequently 

 the seat of a hernial protrusion, and, when it is, the swell- 

 ing may be due to bowel enterocele, or to omentum epip- 

 locele, or to bowel and omentum, together entero-epiplo- 

 cele. Some of the reasons that have been assigned for the 

 frequent presence of hernia in this region are : (1) In the 

 erect position of the body it is against, or on, these parts 

 that the intestines rest ; (2) when pressure is applied to the 

 abdominal contents by contraction of the parietal muscles 

 and diaphragm, the latter acts as a piston, and forces 

 downwards the viscera; (3) the inequalities or fossae refer- 

 red to above, tend to localize the effects of this increased 

 intra-abdominal tension, since the pressure will be exerted 

 on all sides of the interior of the individual depression, 



