1062 



UEIXABY AXD REPRODUCTIVE ORGAXS 



here the two investing fascia? become continuous Avith each other). The anterior 

 l)order crosses the side of the prostate, and is connected with the corresponding 

 })art of the opjiosite muscle by tibrous and smooth muscuLar tissue, which passes 

 between the prostate and rectum. The posterior border is separated from the ante- 

 rior margin of the coccygeus by an indistinct celhilar interspace. 



In the female the anterior fibres of insertion are connected with the side of the 

 vagina, interlacing with the longitudinal tilires of its muscular tissue without be- 

 coming actually inserted into the passage. 



The levator ani is supplied by twigs of the inferior ha?morrhoidal vessels and 

 nerves, and receives also l)ranches from the fourth and fifth sacral nerves. 



Action. — The special action from which the muscle derives its name has been 

 questioned by Riidinger, who believes that its essential function is to compress the 

 rectum. A studv of the direction of the fibres, however, leaves little doubt that 

 the result of the contraction of the muscle as a whole, and in association with its 

 fellow, is to draw forwards the coccyx and elevate the i)elvic floor and viscera, and 



Fig. 650. — Diagram showixg I.ixes of Attachment of the Fasciae 



AND MUSCI.es of THE PELVIS. (W. A.) 



GREATER SACRO-SCIATIC 

 NOTCH 



ISCHIAL SPINE WITH ATTACH- 

 MENTS OF COCCYGEUS AND 

 LEVATOR ANI 



LESSER SCIATIC NOTCH 



Course of 'white line' 



Obturator fascia 



Deep triangular ligament 



Posterior border of 

 perinaeal ledge 



Transversus perinaei 



Obturator fascia 



Levator ani 



Subpubic ligament 



Superficial triangular 



ligament 

 Fascia of Colles 



ISCHIO-CAVERNOSUS AND CRUS 



thus lessen the long diameter of the abdomino-pelvic cavity and aid in the com- 

 pression of the abdominal and pelvic viscera. Its action as a compressor of the 

 rectum is probably unimportant, but it is possible that it exercises some influence 

 upon the circulation in the prostatic plexus and in the large pelvic veins ^-hich 

 occupy the recess betAveen the muscle and the viscera, and may also assist in the 

 expulsion of the prostatic secretion by direct lateral compression of the organ. In 

 the female it may constrict the lower end of the vagina, where the passage lies 

 between the free borders of the two muscles. 



The coccygeus is a thin and rather unimportant plane of muscular fibres, 

 supported I»y and V)lending intimately with the lesser sacro-sciatic ligament. It 

 arises from the inner surface of the ischial spine above the levator ani, and passes 

 backwards and inwards, expanding to Ijccome inserted into the sides of the coccyx, 

 the lateral sacro-coccygeal ligament, and the last two pieces of the sacrum. Its 

 visceral surface looks almost directly forwards and is covered by a continuation of 

 the recto-vesical fascia. Its parietal surface is in contact with the lesser sacro-sciatic 



