COCCTGEUS TRANSVERSUS PERIN^EI. 



263 



bladder, the prostate, and the neighbouring part of the urethra, with cor- 

 responding fibres from the muscle of the opposite side, and blend also with 

 those of the external sphincter and deep transverse perinseal muscles. 



The anterior portion of the levator ani, which arises from the ramus of 

 the pubes, close to the symphysis and above the pubic arch, and also from 

 the adjacent fasciae, is sometimes separated at its origin by areolar tissue 

 from the rest of the muscle. From this circumstance, and from its connec- 

 tion with the prostate gland, it was described by Santorini, and since by 

 AJbinus and Scemmerring, as a distinct muscle, under the name of the 

 levator prostatce. Its fibres pass backwards parallel with the middle line. 



The upper or pelvic surface of the levator ani is in contact with the recto-vesical 

 fascia, the capsule of the prostate, and the lower end of the rectum. The under or 

 perinseal surface, invested by the thin anal fascia, is covered by the fat which occupies 

 the ischio-rectal fossa. The posterior border is continuous with the coccygeus. 



Fig. 203. LEFT HALF OF THE MALE 

 PELVIS, TO SHOW THE LEVATOR ANI AND 

 COCCYGEUS MUSCLES (after Cloquet). 



o, the promontory of the sacrum ; &, 

 the crest of the pubis ; c, the last bone of 

 the coccyx ; d, the spine of the ischium ; 

 e, the symphysis pubis ; /, a small portion 

 of the anal part of the rectum ; g, half 

 the prostate gland ; A, half the bulb and 

 a portion of the penis with the urethra, 

 &c. ; 1, upper part of the obturator in- 

 temus muscle exposed by removing from 

 within it the pelvic fascia ; 2, coccygeus 

 muscle, and above it and between it and d, 

 the sacro-sciatic ligaments ; 3, inner surface 

 of the levator ani ; the white line extending 

 between d and e, shows the place of its 

 origin from the fascia of the pelvis ; below 

 is shown the descent of its fibres to the anus 

 and to the portions of the periiiaeum before 

 and behind it. 



Fig. 203. 



The coccygeus muscle is composed of fleshy and tendinous fibres, forming 

 a thin, flat, and triangular sheet, which arises by its apex from the spine of 

 the ischium and the lesser sciatic ligament, and is attached along its base to 

 the border of the coccyx and the lower part of the sacrum. The fibres of 

 this muscle diverge as they approach the middle line, while those of the 

 levator ani rather converge as they descend. 



The internal or pelvic surface of this muscle assists in supporting the rectum ; its 

 external or under surface rests on the front of the sacro-sciatic ligaments, and on the 

 gluteus maximus muscle. 



The levatores ani and coccygei muscles together have been named somewhat appro- 

 priately by Meyer, the pelvic diaphragm. 



6. GENITOURINARY GROUP. Covered by the special fascia of the perinseum 

 are three muscles, placed superficially the transverse (superficial transverse), 

 the ischio-cavernosus, and the bulbo-cavernosus ; while, situated more deeply 

 between the superficial and deep layers of the subpubic fascia, are the deep 

 transverse musclo and the constrictor of the urethra, sometimes described as 

 one muscle under the name of compressor of the urethra. 



