1172 FEMALE GENERATIVE ORGANS. 



The serous coat is derived from the peritoneum ; it invests the fundus and the 

 whole of the posterior surface of the body of the uterus, but only the upper 

 three-fourths of its anterior surface. In the lo\ver fourth of the posterior sur- 

 face the peritoneum, though covering the uterus, is not closely connected with 

 it, being separated from it by a layer of loose cellular tissue and some large 

 veins. 



The muscular coat forms the chief bulk of the substance of the uterus. In 

 the uniinpregnated state it is dense, firm, of a grayish color, and cuts almost like 

 cartilage. It is thick opposite the middle of the body and fundus, and thin at 

 the orifices of the Fallopian tubes. It consists of bundles of unstriped muscular 

 fibres, disposed in layers, intermixed with areolar tissue, blood-vessels, lymphatic 

 vessels, and nerves. In the impregnated state the muscular tissue becomes more 

 prominently developed, and is disposed in three layers external, middle, and 

 internal. 



The external layer is placed beneath the peritoneum, disposed as a thin plane 

 on the anterior and posterior surfaces. It consists of fibres which pass trans- 

 versely across the fundus, and, converging at each superior angle of the uterus, 

 are continued on the Fallopian tube, the round ligament, the ligament of the 

 ovary : some passing at each side into the broad ligament, and others running 

 backward from the cervix into the sacro-uterine ligaments. 



The middle layer of fibres, which is thickest, presents no regularity in its 

 arrangement, being disposed longitudinally, obliquely, and transversely. It con- 

 tains most blood-vessels. 



The internal or deep layer is the greatly hypertrophied muscularis inucosce of 

 the mucous membrane. It consists of circular fibres arranged in the form of two 

 hollow cones. :he apices of which surround the orifices of the Fallopian tubes, 

 their bases intermingling with one another on the middle of the body of the uterus. 

 At the internal os these circular fibres form a distinct sphincter. 



The mucous membrane is smooth, and closely adherent to the subjacent tissue. 

 It is continuous, through the fimbrinated extremity of the Fallopian tubes, with 

 the peritoneum, and through the os uteri with the lining of the vagina. 



In the body of the uterus it is smooth, soft, of a pale red color lined by colum- 

 nar ciliated epithelium, and presents, when viewed with a lens, the orifices of 

 numerous tubular follicles arranged perpendicularly to the surface. It is unpro- 

 vided with any submucosa, but is intimately connected Avith the innermost layer 

 of the muscular coat, which is regarded as the muscularis mucosae. In structure 

 its corium differs from ordinary mucous membrane, consisting of an embryonic 

 nucleated and highly cellular form of connective tissue in which run numerous 

 large lymphatics. In it are the tube-like uterine glands, which are of small size 

 in the unimpregnated uterus, but shortly after impregnation become enlarged, 

 elongated, presenting a contorted or waved appearance toward their closed extrem- 

 ities, which reaches into the muscularis, and may be single or bifid. They consist 

 of a delicate membrane, lined by an epithelium, which becomes ciliated toward the 

 orifices. In the impregnated uterus the epithelium loses its ciliated character, is 

 thicker and tougher, and is provided with a submucous layer of areolar tissue. 



In the cervix the mucous membrane is sharply differentiated from that of the 

 uterine cavity. It is thrown into numerous transverse folds, which are arranged 

 along an anterior and posterior longitudinal raphe, presenting an appearance which 

 has received the name of arbor vitce. In the upper two-thirds of the canal the 

 mucous membrane is provided with numerous deep glandular follicles, Avhich secrete 

 a clear viscid alkaline mucus ; and in addition, extending through the whole length 

 of the canal, are a variable number of little cysts, presumably follicles, which have 

 become occluded and distended with retained secretion. They are called the ovula 

 Nabothi. The mucous membrane covering the lower half of the cervical canal 

 presents numerous papillae. The epithelium of the upper two-thirds is columnar 

 and ciliated, but below this it loses its cilia, and gradually changes to squamous 

 epithelium close to the external os. 



