THE FEMALE URETHRA 515 



by two prominent rounded folds, the labia. The labia of the vulva (Labia vul- 

 vae) meet above at an acute angle, forming the superior commissure (Commissura 

 dorsalis), which is about two inches (ca. 5 cm.) below the anus. Below they unite 

 to form the thick rounded inferior commissure (Commissura ventralis), which lies 

 about two inches (ca. 5 cm.) l)eliin(l and below the ischial arch. When the labia 

 are drawn apart, a rounded body, about an inch (ca. 2.5 cm.) wide, is seen in the in- 

 ferior commissure; this is the glans clitoridis, the homologue of the glans penis. 

 Overlying it is a thin fold, the prepuce of the clitoris (Prseputium clitoridis). At 

 the anterior extremity of the ventral wall of the vulva, i. e., about four or five 

 inches (ca. 10 to 12 cm.) from the inferior commissure, is the external urethral 

 orifice or meatus urinarius (Orificium urethrse externum). It readily admits the 

 finger and is very dilatable. It is covered by a fold of mucous membrane, the 

 free edge of which is directed backward. 



Structure. — The labia are covered by thin, pigmented, smooth skin, which is 

 richly supplied with sebaceous and sweat glands. This is continuous at a distance of 

 about half an inch (ca. 1 to 1.5 cm.) from the free edge with a thin glandless mucous 

 membrane. Between these is a layer of striped muscle, the constrictor vulvae ; 

 this fuses above with the sphincter ani, and embraces the clitoris below, spreading 

 out laterally at the inferior commissure. It constricts the vulvar orifice and ele- 

 vates the clitoris. The constrictor vestibuli muscle embraces the vulva in front 

 of the preceding; it is joined on either side by a band of unstriped muscle which 

 arises from the first and second coccygeal vertebrae, and is homologous with the 

 proximal part of the retractor penis. It constricts the vulva. Under this muscle 

 in the lateral wall is a flattened, oval body, the bulbus vestibuli (Fig. 453); this is 

 an erectile structure, homologous with the cori)us spongiosum urethrae of the 

 male. It is about two and a half to three inches (ca. 6 to 8 cm.) long, and an inch 

 or more (ca. 3 cm.) wide. It consists of a venous network inclosed in a fibrous 

 capsule, and is supplied with Ijlood by a large branch of the internal pudic artery. 

 The mucous membrane of the vulva is reddish in color, antl forms longitudinal 

 and transverse folds. It presents ventrally two linear series of small papillae 

 which converge toward the inferior commissure; these mark the orifices of the 

 ducts of the glandulae vestibulares minores. On either side of the dorsal wall is a 

 group of eight to ten larger ]:)i-ominences on which the ducts of the glandulae 

 vestibulares majores (of Bartholin) open. 



Quito exceptionally there may l)e found on either side of the urethral orifice the opening of 

 the canals of Gartner (Ductus epoJJphori longitudinales). 



The clitoris is the homologue of the penis. It arises from the ischial arch l)y 

 two crura, which unite to form a body as large as one's little finger. This i)rojects 

 backward into the inferior commissure of the vulva, caj^ped b}- a small rounded 

 glans. The organ is composed of erectile tissue similar to the corpus cavernosum 

 penis. The ischio-cavernosus (or erector clitoridis) is a very feeble muscle which 

 depresses the clitoris. The veins of the clitoris communicate by an intermediate 

 plexus on either side with the bulbus vestibuli. 



THE FEMALE URETHRA 

 The female urethra (Urethra feminina) represents only that part of the canal 

 of the male which lies between the internal urethral orifice and the openings of 

 the ejaculatory ducts. Its length is about two inches (5 cm.), and its lumen is 

 sufficient to admit of the introduction of the finger; it is, however, capable of 

 remarkable dilatation if sufficient care and patience are exercised in the process. 

 It lies centrally on the pelvic floor, and is related and attached dorsally to the 

 vagina. 



