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GENERATION. 



by the broad and round ligaments and by the folds of the peritoneum in 

 front and behind. The delicate layer of peritoneum which forms its external 

 covering extends behind as far down as the vagina, where it is reflected back 

 upon the rectum, and anteriorly, a little below the upper extremity of the 

 neck (os internum), where it is reflected upon the urinary bladder. At the 

 sides of the uterus, the peritoneal covering, a little below the entrance of the 

 Fallopian tubes, becomes loosely attached and leaves a line for the penetra- 



Fio. 278. Muscular fibres of the uterus (Sappey). 



A, fibres of the uterus of the foetus at term ; B, of a woman twenty years of age ; C, of a woman just 



delivered. 



tion of the vessels and nerves. Fig. 277 (C), giving a view of the interior of 

 the uterus, shows a triangular cavity, with two cornua corresponding to the 

 openings of the Fallopian tubes, and very thick walls, the greatest part of 

 which is composed of layers and bands of non-striated muscular fibres. 



The muscular walls of the uterus are composed of non-striated fibres ar- 

 ranged in several layers. These fibres are spindle-shaped and always nucle- 

 ated, the nucleus presenting one or two large granules which have been taken 

 for nucleoli. They are closely bound together, so that they are isolated with 

 great difficulty. In addition to an amorphous, adhesive substance between 

 the muscular fibres, there are many rounded and spindle-shaped cells of con- 

 nective tissue, and a few elastic fibres. The muscular tissue of the uterus is 

 remarkable from the fact that the fibres enlarge immensely during gestation, 

 becoming at that time ten or fifteen times as long and five or six times as 

 broad as they are in the unimpregnated state. They are united into bun- 

 dles or fasciculi, which in certain of the layers interlace with each other in 

 every direction. The fibres are divided into external, middle and internal 

 layers. 



The external, muscular layer, which is very thin but distinct, is closely 



