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THE MUSCLES AND FASCIAE. 



Nerve-supply. A branch from the fourth and fifth sacral nerves. 

 Action. The Coccygei muscles raise and support the coccyx, after it has been 

 pressed backward during defecation or parturition. 



II. A. Muscles and Fasciae of the Perinaeum in the Male. 



Trans versus perinaei. 

 Accelerator urinae. 



Erector penis. 

 Compressor urethrae. 



Superficial Fascia. The superficial fascia of the perinaeum consists of two 

 layers, superficial and deep, as in other regions of the body. 



The superficial layer is thick, loose, areolar in texture, and contains much 

 adipose tissue in its meshes, the amount of which varies in different subjects. In 

 front, it is continuous with the dartos of the scrotum ; behind, it is continuous 

 with the subcutaneous areolar tissue surrounding the anus ; and, on either side, 

 with the same fascia on the inner side of the thighs. This layer should be care- 

 fully removed after it has been examined, when the deep layer will be exposed. 



The deep layer of superficial fascia (Fascia of Colles) is thin, aponeurotic in 

 structure, and of considerable strength, serving to bind down the muscles of the 

 root of the penis. It is continuous, in front, with the dartos of the scrotum ; on 

 either side it is firmly attached to the margins of the rami of the os pubis and 

 ischium, external to the cms penis, and as far back as the tuberosity of the isch- 

 ium ; posteriorly, it curves down behind the Transversus perinaei muscles to join 



FIG. 223. The perineum. The integument and superficial layer of superficial fascia reflected. 



the lower margin of the triangular ligament. This fascia not only covers the 

 muscles in this region, but sends upward a vertical septum from its deep surface, 

 which separates the back part of the subjacent space into two, the septum being 

 incomplete in front. 



The Central Tendinous Point of the Perinaeum. This is a fibrous point in the 

 middle line of the perinaeum, between the urethra and the rectum, being about 

 half an inch in front of the anus. At this point four muscles converge and are 

 attached : viz., the External sphincter ani, the Accelerator urinae, and the two 



