THE ABDOMEN 637 



Colles in the male, and by the postero-superlor layer. The openings 

 in the antero-inferior layer are similar to those in the male, with 

 this exception, that the ducts of the glands of Bartholin do not 

 pierce it as the ducts of the glands of Cowper do in the male, the 

 glands of Bartholin being situated superficial to this layer. The 

 urethral opening is situated i inch below the symphysis pubis. The 

 opening for the vagina, which is of large size, lies below the urethral 

 orifice, from which it is separated by a few fibres. The openings 

 for the arteries of the bulbi vestibuli are situated one on either side 

 of the vaginal opening. The openings for the artery of the corpus 

 cavernosum clitoridis, for the dorsal artery and nerve of the clitoris, 

 and for the superficial perineal vessels and nerves, all of each side, 

 are situated as in the male. 



It is to be noted that the dorsal vein of the clitoris, like the 

 corresponding vessel in the male, passes between the subpubic and 

 transverse pelvic or perineal ligaments. 



The postero-superior layer is similar to the corresponding layer 

 in the male, and it presents openings for the urethra, vagina, and 

 internal pudic vessels and pudic nerves of each side. 



Ischlo-rectal Division. 



The chief characters of the ischio-rectal division in the female 

 are as follows : the aperture of the anus is somewhat nearer the 

 coccyx than in the male, the distance between the ischial tuber- 

 osities is greater than in the male, and the ischio-rectal fossae are 

 wider and shallower than in the male. 



Muscles. — ^The muscles of the female perineum, as compared with 

 those of the male, present certain differences. 



Levatores Ani. — ^The anterior fibres of these muscles embrace 

 the vagina instead of the prostate gland, as in the male. 



Iscliio-cavernosus (erector clitoridis). — ^This muscle replaces the 

 erector penis, and is of small size. 



Bulbo-cavernosus or Sphincter Vaginae. — ^This muscle arises from 

 the central tendinous point, where it meets the external sphincter 

 and superficial transverse perineal muscles. It then passes forwards 

 and divides into two symmetrical parts which surround the vaginal 

 orifice and vestibule, each part closely embracing the outer surface 

 of the corresponding bulbus vestibuli. Anteriorly the two parts 

 become very narrow, and each is inserted into the fibrous sheath of 

 the corpus cavernosum. A few fibres are here detached to be inserted 

 into a tendinous expansion on the dorsum of the clitoris covering 

 the dorsal vein, which vessel would be thereby compressed when the 

 muscle is in action. Some of the inner fibres of the sphincter 

 vaginae are inserted into the mucous membrane of the vestibule. 



The sphincter vaginae is homologous with the bulbo-cavemosi 

 in the male. 



Compressor or Constrictor Urethrae.— This muscle, as in the male, 

 lies between the two layers of the triangular ligament. It is 



