192 MYOLOGY, OR ANATOMY OF MUSCULAR SYSTEM 



fibers end in skin; some decussate across the median line; a 

 few deep ones are continuous from side to side, but a large 

 part blend with the muscles at the "central point." 



The central point of the perineum is the median part of a 

 tendinous septum in which several muscles meet; it is one inch 

 in front of the anus, behind the bulb of the urethra; may be 

 absent. 



The levator ani rises from the pubic body, adherent to and 

 between the obturator and recto vesical fasciae, from the "white 

 line," spine of the ischium, and the upper layer of the tri- 

 angular ligament. 



Insertion. The hinder fibers pass down and in to the coccyx. 

 The foremost run almost directly back to the "central point," 

 the intervening ones to the lower end of the rectum and median 

 aponeurosis between the coccyx and anus, common to the two 

 muscles. 



The coccygem, or levator coccygeus, rises by its apex from the 

 ischial spine and obturator fascia, and is inserted by its base 

 into the margin of the coccyx and lower part of the sacrum. 

 This with the above muscle, on both sides, constitutes the 

 pelvic diaphragm. 



n. The Genitourinary Muscles 



Three on each side and a central deep one. 



Transmrsus Perinei. Origin, low down on inner margin 

 of the ischial ramus passes forward and inward to unite with 

 its fellow, the external sphincter, and bulbocavernosus at the 

 "central point." 



Ischiocavernosus, or Erector Penis. Origin, inner margin 

 of the ramus of the ischium, behind and on each side of the 

 attachment of the crus penis; its tendon spreads over the 

 crus, and is inserted into the outer and under sides of that 

 body at its forepart. 



Bulbocavernosus, or ejaculator urina?, unites with its fellow 

 in a median raphe continued forward from the "central point," 

 the two covering the bulb and part of the corpus spongiosum. 

 Its fibers ascend from the raphe and end on the dorsum of 

 the corpus spongiosum by joining its fellow; at the forepart 

 some pass to the outer side of the corpus cavernosum and 

 send an expansion over the dorsal vessels; some of the pos- 



