THE VULVA 603 
THE VULVA 
The vulva or urogenital sinus (Vestibulum vagine) is the terminal part of the 
genital tract.1 It is continuous in front with the vagina, and opens externally at 
the vulvar cleft below the anus. There is no external line of demarcation between 
the vagina and vulva. The tube is four or five inches (ca. 10-12 cm.) in length, 
measured from the external urethral orifice to the ventral commissure; dorsally 
(from a point vertically opposite to the external urethral orifice) it is considerably 
shorter. It is related dorsally to the rectum and anus, ventrally to the pelvic floor, 
and laterally to the sacro-sciatic ligament, the semimembranosus muscle, and the 
internal pudie artery. The external orifice, the vulvar cleft (Rima vulvz), has the 
form of a vertical slit, four or five inches (ca. 10-12 cm.) high, and is margined 
by two prominent rounded lips, the labia vulva. The labia meet above at an acute 
angle, forming the dorsal commissure (Commissura dorsalis), which is about two 
inches (ca. 5 em.) below the anus. They unite below to form the thick, rounded 
ventral commissure (Commissura ventralis), which lies about two inches (ca. 5 cm.) 
behind and below the ischial arch. When the labia are drawn apart, a rounded 
body, about an inch (ca. 2.5 em.) wide, is seen occupying a cavity in the ventral 
commissure; this is the glans clitoridis, the homologue of the glans penis, and the 
cavity in which it lies is the fossa clitoridis. The roof of the fossa is formed by a 
thin fold, which overlies the glans clitoridis and is attached centrally to it. At 
the anterior extremity of the ventral wall of the vulva, 7. e., four or five inches (ca. 
10-12 em.) from the ventral commissure, is the external urethral orifice (Ori- 
ficium urethre 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 back- 
ward (Fig. 533). 
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. 1-1.5 cm.) from the free edge with a thin, glandless 
mucous membrane. Under the skin there is a layer of striped muscle, the con- 
strictor vulve; this fuses above with the sphincter ani, and embraces the clitoris 
below, spreading out laterally at the ventral commissure. It constricts the vulvar 
orifice and elevates the clitoris. The constrictor vestibuli muscle embraces the 
vulva in front of the preceding; it is deficient dorsally and is joined on either side 
by a band of unstriped muscle, the suspensory ligament of the anus. It constricts 
the vulva. Within this there is an unstriped muscular coat, most of the bundles 
of which are circular. Chiefly between this coat and the mucous membrane there 
is in the lateral wall, just in front of the labia, a flattened, oval body, the bulbus 
vestibuli (Fig. 578); this is an erectile structure, homologous with the corpus 
cayernosum urethre of the male. It is about two and a half to three inches (ca. 
6-8 em.) long, and an inch or more (ca. 3 em.) wide. It is similar in structure to 
the bulb of the corpus cavernosum urethre of the male, and is supplied with blood 
by a large branch of the internal pudie artery. The mucous membrane of the 
vulva is reddish in color, and forms longitudinal and transverse folds. It presents 
ventrally two linear series of small papillae which converge toward the ventral 
commissure; these mark the orifices of the ducts of the glandule vestibulares 
minores. On either side of the dorsal wall is a group of eight to ten larger promi- 
nences on which the ducts of the glandule vestibulares majores open (Fig. 533). 
Quite exceptionally there may be found on either side of the urethral orifice the openings of 
the canals of Gartner (Ductus epodphori longitudinales). 
1 The term vulva is used here in the sense in which it is understood generally by English 
and French veterinarians. In the German works it is applied only to the labia and other struc- 
tures around the external orifice of the urogenital sinus, while the sinus itself is termed the vestibule 
of the vagina (Vestibulum vaginz). 
* Also termed the meatus urinarius. 
