464 



THE MUSCLES AND FASCIAE 



will be seen between it and the deep layer : the subpubic ligament above, close to 

 the pubes ; the dorsal vein of the penis ; the membranous portion of the urethra, 

 and the Compressor urethras muscle ; Cowper's glands and their ducts ; the pudic 

 vessels and nerve ; the artery and nerve of the bulb, and a plexus of veins. 



The Compressor urethras (Constrictor urethrce) surrounds the whole length of 

 the membranous portion of the urethra, and is contained between the two layers 



Anterior layer of 



deep perineal fascia removed, 



showing 



COMPRESSOR URETHRA. 



Internal pudic artery. 

 Artery of the bulb. 

 Cowper's gland. 



^"^- 1^ ^-fc , , ^futf^^ 



FIG. 300. Triangular ligament or deep perineal fascia. On the left side the superficial layer has heen 

 removed. 



of the triangular ligament. It arises, by aponeurotic fibres, from the upper part 

 of the ramus of the os pubis on each side, to the extent of half or three-quarters 

 of an inch : each segment of the muscle passes inward, and divides into two 

 fasciculi, which surround the urethra from the prostate gland behind to the 

 bulbous portion of the urethra in front ; and unite, at the upper and lower 

 surfaces of this tube, with the muscle of the opposite side, by means of a tendinous 

 raphe. 



Actions. The muscles of both sides act together as a sphincter, compressing 

 the membranous portion of the urethra. During the transmission of fluids they, 

 like the Acceleratores urinae, are relaxed, and only come into action at the end of 

 the process to eject the last of the fluid. 



Muscles of the Perinaeum in the Female. 



The Transversus perinsei in the female is a narrow muscular slip, which passes 

 more or less transversely across the back part of the perineal space. It arises by 

 a small tendon from the inner and fore part of the tuberosity of the ischium, and, 

 passing inward, is inserted into the central line of the peringeum, joining in this 

 situation with the muscle of the opposite side, the External sphincter ani behind, 

 and the Sphincter vaginas in front. 



Nerve-supply. The perineal branch of the internal pudic. 



Actions. By their contraction they serve to fix the central tendinous point of 

 the perinfeum. 



The Sphincter vaginae surrounds the orifice of the vagina, and is analogous 

 to the Accelerator urinse in the male. It is attached posteriorly to the central 



