198 MUSCLES OF THE PERINET7M. 



corpus cavernosum, and drawn forwards, to put the membranous 

 portion of the urethra, upon which the muscle is spread out, upon 

 the-stretch. The muscle is, however, better seen in a dissection 

 made from within the pelvis, after having turned down the bladder 

 from its attachment to the os pubis, and removed a plexus of veins 

 and the posterior layer of the deep perineal fascia. 



Fig. 81.* 



The Compressor urethrce (Wilson's and Guthrie's muscles), con- 

 sists of two portions ; one of which is transverse in its direction, and 

 passes inwards, to embrace the membranous urethra ; the other is 

 perpendicular, and descends from the pubis. The transverse portion, 

 particularly described by Mr. Guthrie, arises by a narrow tendinous 

 point, from the upper part of the ramus of the ischium, on each 

 side, and divides into two fasciculi, which pass inwards and slightly 

 upwards, and embrace the membranous portion of the urethra and 

 Cowper's glands. As they pass towards the urethra, they spread 

 out and become fan-shaped, and are inserted into a tendinous raphe 

 upon the upper and lower surfaces of the urethra, extending from 

 the apex of the prostate gland, to which they are attached poste- 

 riorly, to the bulbous portion of the urethra, with which they are 

 connected in front. When seen from above, these portions resemble 

 two fans, connected by their expanded border along the middle line 

 of the membranous urethra, from the prostate to the bulbous portion 

 of the urethra. The same appearance is obtained by viewing them 

 from below. 



* The muscles of the perineum. 1. The acceleratores urinae muscles: the figure 

 rests upon the corpus spongiosum penis. 2. The corpus cavernosum of one side. 3. 

 The erector penis of one side. 4. The transversus perinei of one side. 5. The trian- 

 gular space through which the deep perineal fascia is seen. 6. The sphincter ani ; its 

 anterior extremity is cut off. 7. The levator ani of the left side ; the deep space be- 

 tween the tuberosity of the ischium (8) and the anus, is the ischio-rectal fossa; the same 

 fossa is seen upon the opposite side. 9. The spine of the ischium. 10. The leftcoccy- 

 weus muscle. The boundaries of the perineum arc well seen in this engraving. 



