DISSECTION OF THE PELVIS. 357 



aroimd the extremity of the A'ulva, being confounded with the sphincter 

 ani above, while inferiorly some of the fibres are attached to the base 

 of the cUtoris, and others are attached to the inner surface of 

 the skin below the inferior commissure. When the muscle contracts, it 

 constricts the orifice of the vulva. Its lower fibres may frequently be 

 observed to contract after micturition, depressing the inferior commissure 

 and exposing the clitoris, which is simvdtaneously erected. 



The Clitoris. This small erectile body is the homologue of the male 

 penis minus the urethra. It is lodged within the inferior commissure of 

 the vulva, and presents a base, or attached extremity, a body, and a free 

 extremity. The base is bifid, and attached to the ischial arch by the 

 branches, or crura, each crus being covered by a rudimentary erector 

 ditoridis muscle — the homologue of the erector penis. The body of the 

 clitoris, which is from two to three inches in length, projects backwards 

 and upwards, and is composed of right and left halves like the corpora 

 cavernosa of the penis. The free extremity is formed by a rudimentary 

 glans, which is provided with a mucous cap analogous to the prepvice. 

 The clitoris is composed of erectile tissue resembling that of the 

 • penis. 



The Vestibular Bulb. This will be exposed by the removal of the 

 posterior constrictor muscle. It is an erectile body composed of right 

 and left halves, each of which is placed at the side of the vulvar cavity 

 (the vestibule), between the posterior constrictor and the mucous 

 membrane. Inferiorly the two halves of the organ are in communica- 

 tion with one another, and with the erectile tissue of the clitoris, 

 and superiorly each terminates at the side of the vulva by a rounded 

 end. The bulb is the homologue of the corpus spongiosum of the 

 penis. 



Directions. — The pelvic viscera must now be removed to allow an 

 examination of the structure and interior of the organs just considered. 

 This is to be effected by cutting the meso-rectum and the peritoneal 

 ligaments of the bladder, carrying the knife above the anus and below 

 the inferior commissure of the vulva, and destroying the vascular 

 and connective-tissue attachments of the various organs to the pelvic 

 walls. The entire generative apparatus will thus be removed along 

 with the urinary bladder and the rectum. The latter organ shoidd be 

 dissected from the vagina and vulva (for its structure see page 344), 

 and the other viscera examined seriatim. The canal of the vidva and 

 vao-ina is to be exposed by a mesial incision on the upper wall of these 



organs. 



The Canal of the Vulva. This, as already stated, is a tubular 

 passage about five inches in length. When removed from the body 

 and inflated, it assumes a large calibre, but ordinarily its walls are 

 in contact, Tracing the canal in an order inverse to that followed 



