756 EMBRYOLOGY 



extremity is somewhat rounded and is attached to one of the fimbriae 

 of the Fallopian tube. The inner extremity is more pointed and is 

 attached to the side of the uterus by means of the ligament of the ovary. 

 This ligament is shown in Fig. 197 (/, /). It is a rounded cord, com- 

 posed of non-striated muscular fibres spread out on the attached extrem- 

 ity of the ovary and the posterior surface of the uterus, and is covered 

 by peritoneum. The weight of the ovary is sixty to one hundred grains 

 (3.9 to 6.5 grams), and it is largest in the adult virgin. Its attached 

 border is called the hilum ; and at this portion the vessels and nerves 

 penetrate. The surface presents rounded translucent elevations, pro- 

 duced by distended Graafian follicles, with little cicatrices indicating the 

 situation of ruptured follicles. There may also be seen, between the 

 distended follicles, corpora lutea in different stages of atrophy. 



After the peritoneum has reached the ovary, its fibrous layer be- 

 comes indistinct and fuses with the fibrous stroma of the ovary itself. 

 The peritoneal endothelium here undergoes a change, and the cells on 

 the surface of the ovary are cuboidal and in a single layer. This 

 change in the structure of the peritoneum is abrupt and is indicated by 

 a distinct line surrounding the hilum of the ovary. 



On making a section of the ovary, it is readily seen with the naked 

 eye that the organ is composed of two distinct structures ; a cortical 

 substance, sometimes called the tunica albuginea, which is about ^V of 

 an inch (i millimeter) in thickness, and a medullary substance contain- 

 ing a large number of bloodvessels. The cortical substance alone con- 

 tains the Graafian follicles. The external layer of this is denser than 

 the deeper portion, but there is no distinct fibrous membrane such as is 

 sometimes described under the name of tunica albuginea. 



The cortical substance of the ovary consists of connective tissue in 

 several layers, the fibres of which are continuous with the looser fibres 

 of the medullary portion. In the substance of this layer, are embedded 

 the ova, enclosed in the sacs called Graafian follicles. This layer con- 

 tains a few bloodvessels coming from the medullary portion, which 

 surround the follicles. 



The medullary portion of the ovary is very vascular and is composed 

 of small bands, or trabeculae of connective tissue, with non-striated 

 iriuscular fibres. The bloodvessels, which penetrate at the hilum, are 

 large and convoluted, especially at the hilum itself, where there is a 

 mass of convoluted veins, forming a sort of vascular bulb. In the 

 medullary portion, which is sometimes called the vascular zone, the 

 muscular fibres follow the vessels, in the form of muscular sheaths. 



In addition to the bloodvessels, the ovary receives nerves from the 

 spermatic plexus of the sympathetic, the exact mode of termination of 



