488 



THE MUSCULAK SYSTEM. 



Nerve-Supply. Deep branch of the perinea! nerve (pudendal, S. 3. 4.). 



Actions. In the male. The bulbocavernosus contracts the urethra in the emission of 

 urine and semen, and is an accessory muscle in erection of the penis. 



In the Female. The muscle contracts the vaginal orifice, and compresses the bulb of the 

 vestibule of the vagina. 



M. Ischiocavernosus. The ischiocavernosus (O.T. erector penis), in the 



male, covers the crus penis. It arises from the ischial tuberosity and the sacro- 

 tuberous ligament. 



Passing forwards, it is inserted by a fascial attachment into the inferior surface 

 of the crus penis, and into the lateral and dorsal aspects of the corpus caver- 

 nosum penis. 



The ischiocavernosus (O.T. erector clitoridis), in the female, has a similar dis- 

 position, but is of much smaller size than in the male. 



The pubocavernosus is an occasional slip arising from the pubic ramus, and inserted into 

 the dorsum of the penis. It corresponds to the levator penis of lower animals. 

 Nerve-Supply. Deep branch of the perineal nerve (pudendal, S. 3. 4.). 

 Action. The muscle assists in erection of the penis (or clitoris). 



Corpus cavernosum penis 

 (cut) 



Nerve to corpus 



cavernosum penis 



Nerve to dorsum of penis 



SPHINCTER URETHRA 



MEMBRANACEA: 



Nerve to bulb 



Fascia superior of uro- 



genital urophragm 



Pudendal nerve 



Bulb of penis 



Fascia inferior of 

 urogenital diaphragm 



Crus penis 



LEVATOR ANI 



FIG. 433. THE FASCLE OF THE UROGENITAL DIAPHRAGM OF THE PERINEUM, 

 AND THE TERMINATION OF THE PUDENDAL NERVE. 



Diaphragma Urogenitale. The sphincter urethrse membranacese and tb 

 transversus perinei profundus constitute the deeper muscular stratum of th 

 perineum and form the urogenital diaphragm. They lie between two layers c 

 fascia called the fascia inferior, and fascia superior of the urogenital diaphragm 

 (O.T. superficial and deep layers of the triangular ligament). 



M. Sphincter Urethras Membranacese. The sphincter of the membranoi 

 urethras (O.T. compressor urethrse) arises from the inferior part of the pubic ramu 

 and is directed medially, its fibres radiating so as to enclose the membranous urethr 



It is inserted into a median raphe, partly anterior to the urethra, but for tl 

 most part posterior to it. The fibres most intimately related to the urethra for 

 a muscular sheath for the canal, and have no bony attachments. 



M. Transversus Perinei Profundus. The transversus perinei profundi 

 consists of a bundle of fibres on each side which arises from the inferior ramus of t. 

 ischium just below the sphincter urethrse membranacese. It is inserted into 

 median raphe continuous with that of the sphincter urethrse membranacese. T. 

 muscle, in fact, constitutes a separate bundle below and behind the sphincter. 



The ischiopubicus is a term applied to a feeble bundle of fibres which, wl: 

 present, lies above and in front of the sphincter urethrse membranacese. It arises fr i 





