THE PERITONEUM. 



1743 



distinct, and often extends inward under the obliterated hypogastric artery. Farther 

 out a very small fold (plica epigastrica), caused by the deep epigastric artery, runs 

 upward and inward from the external iliac artery just as the latter passes under Pou- 

 part's ligament. The external ox lateral inguinal fossa (fovea inguinalis lateralis) 

 is theoretically just external to this fold, but the fold is barely raised and a fossa not 

 easily made out. The internal abdominal ring (annulus inguinalis abdominalis) is 

 in this fossa, about i cm. above the middle of Poupart's ligament. A slight fold, 

 caused by the vas deferens or the round ligament, is described as running downward 

 from the ring into the pelvis ; the fact is, however, that the structure can be only 

 indistinctly seen through the peritoneum, and a raised fold is rare. It forms the 

 outer border of the slightly marked yW«(?;7?/ depression (fovea femoralis) opposite the 

 y^-w^ra/ r/;/^ (annulus cruralis), between the pubes and Poupart's ligament. The 

 peritoneum is continued laterally on either side without presenting any feature that 

 calls for description until it reaches the ascending or the descending colon. All 

 the serous covering anterior to these structures is derived from the parietal perito- 

 neum ; that posterior to them is derived from the mesenteries of the colons which 



Fig. 146S. 



Umbilicus 



-Umbilical vein 



Rectus muscle ^Z""* 



External inguinal 

 fossa 



Anterior ' •' 

 crural nerve 



Ext. iliac artery ,,. 



External iliac vein 



Internal inguinal 

 fossa 



Supravesical fossa 



Summit of bladder 



Anterior superior 

 iliac spine (cut) 



Median umbilical 

 fold (urachus) 



Lateral 

 umbilical fold 

 ! Epigastric fold 



-^ — Internal 



abdominal ring 



— Vas deferens 



Peritoneum 



Bladder (cut) 

 Pubic bone (cut) 



Frontal section of formalin subject, showing posterior aspect of abdominal wall, covered with peritoneum. 



have fallen over onto the posterior abdominal walls. It will be considered later. 

 The parietal peritoneum is also to be traced onto the under surface of the dia- 

 phragm until far back it meets the folds derived from the mesenteries. On either 

 side of the bundle of fibres arising from the ensiform cartilage there is an inter- 

 ruption in the muscle of the diaphragm, where only areolar tissue separates the 

 peritoneum and the pleura or pericardium. 



The parietal peritoneum is continued into the pelvis, where it meets the mesen- 

 tery of the colon and is continued oyer the bladder, and in the female over the 

 uterus and Fallopian tubes. Nowhere is the comparison to a wall-paper so apt as 

 here, where the peritoneum can be traced from the walls over the inequalities 

 formed by the upper surfaces of the pelvic organs. The depression between the 

 bladder and the rectum in the male, the recto-vesical poiich (excavatio recto-vesicalis), 

 in the female is subdivided into the utero-vesical pouch (excavatio utero-vesicalis) and 

 the rcdo-nterine pouch (excavatio recto-uterina). The latter and deeper, also known 

 as the po2ich of Douglas (cavum Douglasi), is bounded laterally by the tdero-sacral 

 folds (plicae recto-uterinae), which pass from the lower part of the uterus backward 



