LABIA CLITORIS. 549 



the front of the os pubis. Its cellular tissue is loaded with adipose 

 substance, and the surface covered with hairs. 



The Labia majora are two large longitudinal folds of integument, 

 consisting of fat and loose cellular tissue. They enclose an elliptical 

 fissure, the common urino-sexual opening or vulva. The vulva re- 

 ceives the inferior opening of the urethra and vagina, and is bounded 

 anteriorly by the commissura superior, and posteriorly by the com- 

 missura inferior. Stretching across the posterior commissure is a 

 small transverse fold, the frcenulum labiorum or fourchette, which is 

 ruptured during parturition, and immediately within this fold is a 

 small cavity, the fossa navicularis. The breadth of the perineum is 

 measured from the posterior commissure to the margin of the anus, 

 and is usually not more than an inch across. The external surface 

 of the labia is covered with hairs ; the inner surface is smooth, and 

 lined by mucous membrane, which contains a number of sebaceous 

 follicles, and is covered by a thin cuticular epithelium. The use of 

 the labia majora rs to favour the extension of the vulva during par- 

 turition ; for, in the passage of the head of the fetus the labia are 

 completely unfolded and effaced. 



The Labia minora, or nympha are two smaller folds situated 

 within the labia majora. Superiorly they are divided into two pro- 

 cesses, which surrounds the glans clitoridis, the superior fold form- 

 ing the prseputium clitoridis, and the inferior its frsenulum. Infe- 

 riorly, they diminish gradually in size, and are lost on the sides of 

 the opening of the vagina. The nymphas consist of mucous mem- 

 brane, covered by a thin cuticular epithelium. They are provided 

 with a number of sebaceous follicles, and contain, in their interior, a 

 layer of erectile tissue. 



The Clitoris is a small elongated organ situated in front of the os 

 pubis, and supported by a suspensory ligament. It is formed by a 

 small body, which is analogous to the corpus cavernosum of the 

 penis, and, like it, arises from the ramus of the os pubis and ischium 

 on each side, by. two crura. The extremity of the clitoris is called 

 its glans. It is composed of erectile tissue, enclosed in a dense 

 layer of fibrous membrane, and is susceptible of erection. Like the 

 penis, it is provided with two small muscles, the erectores clitoridis. 



At about an inch beneath the clitoris is the entrance of the vagina, 

 an elliptical opening, marked by a projecting margin. The entrance 

 to the vagina is closed in the virgin by a membrane of a semilunar 

 form, which is stretched across the opening ; this is the hymen. 

 Sometimes the membrane forms a complete septum, and gives rise 

 to great inconvenience by preventing the escape of the menstrual 

 effusion. It is then called an imperforate hymen. The hymen must 

 not be considered a necessary accompaniment to virginity, for its 

 existence is very uncertain. When present it assumes a variety of 

 appearances : it may be a membranous fringe, with a round open- 

 ing in the centre, or a semilunar fold, leaving an opening in front ; 

 or a transverse septum, having an opening both in front and behind ; 

 or a vertical band with an opening at either side. 



