THE PEL VIC FASCIA 



449 



contained between the two layers of the triangular ligament. It arises, by apon- 

 eurotic fibres, from the junction of the rami of the os pubis and ischium, to the 

 extent of half or three-quarters of an inch the point w T here the crura penis join 

 the transverse ligament of the perineum and the layers of the triangular liga- 

 ment; each segment of the muscle passes inward, and divides into tw r o fasciculi, 

 w r hich surround the membranous urethra and unite, at the upper and lower 

 surfaces of this tube, w r ith the muscle of the opposite side by means of a tendinous 

 raphe. This muscle is frequently discovered in two portions, an anterior and a 

 posterior, separated by a distinct interval. In such cases the posterior fibres are 

 called the transversus perinei profundus, and the anterior fibres are called the 

 sphincter urethrae membranaceae. The Compressor urethrae in the female arises 

 as in the male; passing mesally, likewise, it divides into two fasciculi; these latter, 

 however, have not the same intimate functional relationship to the urethra as has 

 the muscle of the male. One fasciculus passes ventrad of the urethra to blend 

 with its opposite fellow; the posterior fascicle inserts itself into the lateral 

 vaginal wall. 



Nerve-Supply. The perineal branch of the internal pudic. 



Actions. The muscles of both sides act together as a sphincter, compressing the mem- 

 branous portion of the urethra. During the transmission of fluid they, like the Accelerators 

 urinae, are relaxed, and come into action only at the end of the process, to eject the last drops of 

 the fluid. 



The Pelvic Fascia. 



The pelvic fascia binds strongly together the pelvic structures, supports the 

 bloodvessels, nerves, and lymphatics, and strengthens the floor of the cavity. 

 Above, it is loosely connected to the back part of the iliopectineal line, and is 

 continuous here with the iliac fascia. Posteriorly, over the sacrum, it is very 



ANTERIOR- 

 SUPERIOR 

 SPINES 



POUPARTS 

 LIGAMENT 



OBTURATOR 

 ARTERY 



WHITE LINE 



GREATER 



SACROSCIATIC 



LIGAMENT 



FASCIA OF 



LEVATOR ANI 



MUSCLE 



TUBEROSITY 

 OF ISCHIUM 



FIG. 341. Pelvic fascia (semidiagrammatic). 



thin and lies ventrad to the Pyriformis muscle and to the sacral plexus of 

 nerves. This part is often called the fascia of the Pyriformis, and extends outward 

 along- the muscle into the gluteal region. At its sacral attachments around the 

 margins of the sacral foramina it comes into intimate association with and en- 



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