THE LEVATOR ANl. 



343 



the male, behind the vulval orifice in the female. The tendinous structure is, how- 

 ever, not unfrequently entirely absent, in which case the muscles are directly con- 

 tinuous with one another. 



The levator ani is a broad fleshy layer which extends from the anterior and 

 lateral parts of the pelvic wall downwards and inwards to the middle line, and 

 forms, together with its 

 fellow of the opposite 

 side, a muscular floor 

 to the greater part of 

 the pelvic cavity. It 

 takes origin from the 

 pelvic surface of the 

 body of the pubis by thin 

 tendinous fibres, placed 

 between and intimately 

 adherent to the pubic 

 attachments of the ob- 

 turator and recto-vesical 

 fasciae, from the pelvic 

 fascia along the line of 

 origin of the recto-vesi- 

 cal fascia, and to a slight 

 extent from the ischial 

 spine. Some fasciculi 

 are also frequently added 

 to the fore part of the 

 muscle from the upper 

 layer of the deep peri- 

 neal fascia. The hinder 

 fibres pass downwards 

 and inwards to the lateral 

 margin of the coccyx ; 

 the foremost ones run 

 almost directly back- 

 wards to the central 

 point of the perineum ; 

 and the intervening 

 ones descend with 

 varying degrees of 

 obliquity to the lower 

 end of the rectum and 

 to a narrow median 



aponeurosis common to the muscles of the two sides between the tip of the coccyx 

 and the anus. 



PROSTATE 



Fig. 302. LEVATOR ANI AND COCCYGEUS MUSCLES OF THK RIGHT 

 SIDE, FROM WITHIN. (Drawn by T. W. P. Lawrence.) 



i.sp., ischial spine ; gt.s.s.L, great sacro-sciatic ligament. 



The levator ani is divided by a cleft beginning just below the obturator canal into two 

 portions, only the anterior of which is directly connected with the rectum. This portion (the 

 pubo-coccygeus of Savage) includes the fibres springing from the pubis and the adjoining part 

 of the f ascial origin, and is to some extent bilaminar : its outer or superficial fibres run back- 

 wards over the side of the prostate and rectum, being closely applied to the highest bundles 

 of the external sphincter, of which they seem to form a continuation upwards, and becoming 

 united with the corresponding part of the opposite side behind the bowel are inserted into the 

 tip of the coccyx. The inner or deep fibres are partly inserted into the wall of the rectum, 

 making their way between the external and internal sphincters to join the longitudinal fibres 

 of the bowel ; but a few anterior ones meet and decussate with those of the opposite muscle 



