374 



THE MUSCLES AND FAWI.K 



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

 and dorsal nerve of the penis ; the artery and nerve of the bulb, and a plexus of 

 veins. 



The deep layer of the ligament (superior layer of the triangular ligament) is 

 derived from the obturator fascia and stretches across the pubic arch. If the 

 obturator fascia is traced inward after covering the Obturator internus muscle, 

 it will be found to be attached by some of its deeper or anterior fibres to the inner 

 margin of the ischio-pubic ramus, while its superficial or posterior fibres pass over 

 this attachment to become the superior layer of the triangular ligament. Behind, 

 this layer of the fascia is continuous with the inferior layer and with the fascia of 

 Colles, and in front it is separated from the apex of the prostate gland through the 

 intervention of a prolongation of the recto-vesical fascia. It is pierced by the 

 urethra, or rather consists of two halves which are separated in the middle line by 

 the urethra passing between them. 



TRANSVERSUS 

 PERIN/EI. 



TUBER ISCHII, 



FIG. 227. Muscles of the female perinseum. 



The Compressor urethras (Constrictor urethra*) surrounds the whole length of 

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

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

 the rami of the os pubis and ischium, 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 por- 

 tion 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. 



Nerve-supply. The perinea! branch of the internal pudic. 



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 urinre, are relaxed, and come into action only at the end of 

 the process, to eject the last drops of the fluid. 



