392 THE ABDOMEN AND PELVIS 



pelvic wall, where it is closely related to the medial surface of 

 the ovary (Fig. 117). 



The part of the tube which is embedded in the uterine wall 

 is known as the pars uterina. Lateral to it, the tube possesses 

 for a short distance well-marked longitudinal and circular 

 muscular coats. In this portion, which is termed the isthmus, 

 the lumen is very small. Lateral to the isthmus, the muscular 

 coat is not so strongly developed, but the mucous coat is very 

 much thicker. This part of the tube is known as the ampulla, 

 and its extremity widens out into the infundibulum, which is a 

 funnel-like depression, the walls of which are formed by numerous 

 narrow processes, called the fimbria. These processes project 

 from the broad ligament, and are completely covered by 

 peritoneum. One of them, the fimbria ovarica, is constantly 

 attached to the upper pole of the ovary. At the bottom of the 

 infundibulum, the uterine tube communicates with the peritoneal 

 cavity through the ostium abdominale, and at this point the 

 peritoneal endothelium merges into the ciliated epithelium 

 which lines the tube. 



As the ova are discharged from the ovary, they pass at once 

 into the peritoneal cavity, and only those that gain entrance to 

 the ostium abdominale have any chance of becoming fertilised. 

 Occasionally, a fertilised ovum fails to be carried along the 

 tube into the uterus and continues to develop in the tube itself. 

 This condition is known as tubal gestation, and as the ovum 

 enlarges, gives rise to abdominal symptoms, which are frequently 

 misinterpreted. Tubal abortion may occur through the ostium 

 abdominale, and in this case the haemorrhage varies in severity. 

 Occasionally, it is excessive and calls for surgical interference. 

 Failing a tubal abortion, the ovum increases in size until the 

 uterine tube ruptures, when the extent of the subsequent 

 haemorrhage will depend on the site of the rupture. If the 

 tube gives way in the lower two-fifths of its circumference, the 

 haemorrhage occurs between the two layers of the broad ligament, 

 and is consequently limited in amount. On the other hand, 

 if the tube ruptures in the upper three-fifths of its circumference, 

 the haemorrhage occurs into the peritoneal cavity, and unless 

 it is restricted by the partial obliteration of the cavity owing 

 to adhesions, it is so severe that immediate laparotomy is 

 imperative. 



The Ovary is an almond-shaped body about i to i| inches 

 long by half an inch wide. It projects from the posterior 



