THE MUSCLES OF THE UROGENITAL REGION IN THE MALE 427 



The Central Tendinous Point of the Perineum. This is a fibrous point in the middle 

 line of the perineum, between the urethra and anus, and about 1.25 cm. in front 

 of the latter. At this point six muscles converge and are attached: viz., the 

 Sphincter ani externus, the Bulbocavernosus, the two Transversi perinsei super- 

 ficiales, and the anterior fibers of the Levatores ani. 



Fio. 406. Muscles of male perineum. 



The Transversus perinssi superficial ( Transversus perincei; Superficial transverse 

 perineal muscle) is a narrow muscular slip, which passes more or less transversely 

 across the perineal space in front of the anus. It arises by tendinous fibers from 

 the inner and forepart of the tuberosity of the ischium, and, running medialward, 

 is inserted into the central tendinous point of the perineum, joining in this situa- 

 tion with the muscle of the opposite side, with the Sphincter ani externus behind, 

 and with the Bulbocavernosus in front. In some cases, the fibers of the deeper 

 layer of the Sphincter ani externus decussate in front of the anus and are con- 

 tinued into this muscle. Occasionally it gives off fibers, which join with the 

 Bulbocavernosus of the same side. 



Variations are numerous. 

 External sphincter. 



It may be absent or double, or insert into Bulbocavernosus or 



