FEMALE PERINEUM 371 



The sphincter vagina is the representative of the bulbo- 

 cavernosus of the male. It is a true sphincter muscle, and 

 consists of two halves, which are placed one on each side 

 of the vaginal orifice and vestibule, closely adapted to the 

 surfaces of the two halves of the vaginal bulb. Posteriorly 

 the fibres of opposite sides unite behind the vaginal opening, 

 and are attached to the central point of the perineum, some 

 of the fibres intermixing with those of the sphincter ani. 

 Anteriorly the two portions of the muscle become narrower, 

 and, converging towards the middle line, are attached to the 

 sides of the clitoris. In some cases a small fasciculus, on each 

 side, may be observed to reach the dorsum of the clitoris and 

 there gain insertion into a tendinous expansion which lies 

 superficial to the dorsal vein. This fasciculus is comparable 

 with the anterior fibres of the bulbo-cavernosus of the male, 

 which embrace the circumference of the body of the penis. 



Perineal Triangle. The dissector should now observe that 

 the three perineal muscles form the sides of a small triangle, 

 the floor of which is constituted by the inferior fascia of the 

 urogenital diaphragm. 



Perineal Body. It has been already stated that the term 

 " perineum " is confined by the obstetrician to the narrow 

 interval between the frenulum pudendi and the anus. Now 

 that this part has been dissected, it will be seen to consist of an 

 indefinite mass of fibrous and muscular tissue, which occupies 

 the interval between the anal canal and the vagina. This is 

 known as the perineal body. Muscular tissue belonging to the 

 sphincter ani, levatores ani, and sphincter vaginae, together with 

 the central point of the perineum, enter into its constitution. 



Dissedion.T\\e. sphincter vaginae should now be carefully raised from 

 the surface of the bulb, and the ischio-cavernosus from the surface of the 

 crus clitoridis. The transversus perinei superficialis may be removed at 

 the same time. 



Bulb of the Vestibule. The bulb of the vestibule is now 

 displayed. It consists of two oblong bodies, composed of 

 erectile tissue, placed one on each side of the vestibule and 

 entrance to the vagina. Somewhat narrow in front, they 

 expand as they pass backwards, and each is invested by a 

 fibrous capsule derived from the urogenital diaphragm, upon 

 the inferior surface of which they rest. Laterally each presents 

 a rounded convex surface which is coated with the sphincter 

 vaginae muscle, whilst each erectile mass rests, medially, upon 



