THE ABDOMEN ' 885 



and forms rather more than half of the tube. It is larger than 

 the isthmus, less resistant (being chiefly mucous in structure), and 

 tortuous. Its diameter gradually increases in the distal direction, 

 the average being about 7 millimetres. The ampulla at its outer 

 end becomes constricted to form the neck, which presents the 

 ostium abdominale, opening into the pelvic cavity, its diameter 

 being about 2 millimetres. It is in this situation where the general 

 cavity of the peritoneum in the female is continuous with the lumen 

 of the Fallopian tube, and through it with the cavity of the uterus 

 and vagina. Beyond the neck the tube expands in the form of 

 a funnel, called the infundihulum or pavilion, in the body of which 

 the ostium abdominale is situated. The circumference of the in- 

 fundihulum is broken up into a number of irregular fringes, called 

 fimbricB, and the outer end of the tube is hence called the corpus 

 fimbriatum. The larger fimbriae are broken up into smaller filiform 

 processes. The outer surfaces of the fimbriae, which look into the 

 pelvic cavity, are covered by peritoneima, but the inner surfaces, 

 which look into the infundibulum, are covered by mucous mem- 

 brane continuous with that of the Fallopian tube. At the free 

 margins of the fimbriae the peritonemn, with its endothelial cells, 

 becomes continuous with the mucous membrane, which is covered 

 by ciliated columnar epitheUum. One of the fimbriae, which is 

 larger and longer than the others, is called the ovarian fimbria, 

 and is connected %vith the upper or tubal pole of the ovary usually 

 directly, but sometimes by a deUcate fibrous band. This fimbria 

 presents a longitudinal furrow, which serves as a channel of com- 

 munication between the ostium abdominale and the ovary. 



For the structure and development of the Fallopian tubes, see 

 Index. 



Uterus. — ^The uterus is a hollow muscular organ, which receives 

 at its superior angles the Fallopian tubes, and opens below into 

 the upper part of the anterior wall of the vagina. Through the 

 Fallopian tubes it receives the ova at periodical intervals, and, 

 when an ovum becomes impregnated, the utenis retains it during 

 development, and thereafter expels the foetus through the vagina. 

 The virgin uterus Ues upon the superior surface of the bladder, 

 and is usually inclined to the right of the middle Hue. Above it 

 there are a portion of the pelvic colon and usually a few coUs of the 

 ileum. At its lower end is the vagina, and the broad ligament 

 stretches from either side. It is somewhat pyriform, the wide end 

 being directed upwards and forwards, and is flattened from before 

 backwards. It is firm and resistant to the touch, on account of 

 its very thick musdmar walls. Its average length is 3 inches, the 

 breadth at the upper part being 2 inches, and the thickness i inch. 

 The organ is divided into a fimdus, body, and cervix. 



The fundus is that portion which lies above the level of a line 

 connecting the superior angles, where the Fallopian tubes pass 

 through the uterine wall. It is convex from side to side, and also 



