546 STRUCTURE OF UTERUS. 



original bicornute condition of the organ, with the commencement 

 of the Fallopian tubes. In the canal of the cervix uteri are two 

 or three longitudinal folds to which numerous oblique folds converge 

 so as to give the idea of branches from the stem of a tree ; hence 

 this appearance -has been denominated the arbor mice, uterina. Be- 

 tween these folds, and around the os uteri, are numerous mucous 

 follicles. It is the closure of the mouth of one of these follicles, 

 and the subsequent distension of the follicle with its proper secre- 

 tion, that occasions those vesicular appearances so often noticed 

 within the mouth and cervix of the uterus, called the ovula of 

 Nabotfi. 



Structure. The uterus is composed of three tunics ; of an external 

 or serous coat derived from the peritoneum, which constitutes the 

 duplicatures on each side of the organ called the broad ligaments ; 

 of a middle or muscular coat, which gives thickness and bulk to the 

 uterus ; and of an internal or mucous membrane, which lines its in- 

 terior, and is continuous on the one hand with the mucous lining of 

 the Fallopian tubes, and on the other with that of the vagina. In 

 the unimpregnated state the muscular coat is exceedingly condensed 

 in texture, offers considerable resistance to section with the scalpel, 

 and appears to be composed of white fibres inextricably interlaced 

 and mingled with blood-vessels. In the impregnated uterus the 

 fibres are of large size and distinct, and are disposed in two layers, 

 superficial and deep. The superficial layer consists of fibres which 

 pursue a vertical direction, some being longitudinal and others 

 oblique. The longitudinal fibres are found principally upon the 

 middle line, forming a thin plane upon the anterior and posterior 

 face of the organ and upon its fundus. The oblique fibres occupy 

 chiefly the sides and fundus. At the angles of the uterus the fibres 

 of the superficial layer are continued outwards upon the Fallopian 

 tubes, and into the round ligaments and the ligaments of the ovaries. 

 The deep layer consists of two hollow cones of circular fibres having 

 their apex at the openings of the Fallopian tubes, and by their bases 

 intermingling with each other on the body of the organ. These 

 fibres are continuous with the deep muscular layer of the Fallopian 

 tubes, and indicate the primitive formation of the uterus by the 

 blending of these two canals. Around the cervix uteri the muscular 

 fibres assume a circular form interlacing with and crossing each 

 other at acute angles. The mucous membrane is provided with a 

 columnar ciliated epithelium, which extends from the middle of the 

 cervix uteri to the extremities of the Fallopian tubes. 

 . Vessels and Nerves. The Arteries of the uterus are the uterine 

 from the internal iliac, and the spermatic from the aorta. The 

 veins are very large and remarkable ; in the impregnated uterus 

 they are called sinuses, and consist of canals channeled through the 

 substance of the organ, being merely lined by the internal membrane 

 of the veins. They terminate on each side of the uterus in the 

 uterine plexuses. The lymphatics terminate in the lumbar glands. 



