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U.S. NATIONAL MUSEUM BULLETIN 273 



PERINEAL MUSCULATURE- — MALE 



M. bulbospongiosus (fig. 21) : This muscle surrounds the bulb of 

 the penis and the crura of the corpora cavernosa. Its fibers arise 

 from the longitudinal raphe along the superficial aspect of the bulbus 

 and corpus spongiosum penis. A muscular coat is formed for these 

 structures as the bundles in the anal half of the bulbospongiosus 

 ascend almost perpendicularly toward their insertion in the pars 

 membranacea of the urogenital sphincter, and tliose in the more ventral 

 portion follow an oblique ventrocranial course around the corpus 

 spongiosum and tlie crura of the cavernous bodies on their way to 



Figure 2L — Perineal musculature, caudal aspects of Cd 2 and hemal arch 2 (1, m. ischio- 

 urethralis; 2, m. ischiocavcrnosus; 3, m. ischiocaudalis; 4, m. sphincter ani externus; 

 5, m. pubocaudalis; 6, m. iliocaudalis; 7, m. sphincter urethrae; 8, m. bulbocavernosus). 



