[SCHIO-RBCTAL FOSSA. 



239 



I'ectum and the ischial part of the hip-bone. It is a somewhat 

 n'ramidal hollow, which is larger behind than before, and diminishes form ; 

 n width as it sinks on the inner side of the hip-bone. Its width is 

 ibont one inch at the surface ; and its depth about two inches at the dimensions 

 outer side. It is filled by a soft granular fat. 



The inner or longest side of the space is very oblique, and is boundaries, 

 brmed by the levator ani muscle (D), together with the coccygeus at 

 the back ; but the outer side is vertical, and is formed by the obturator 



FIG. 91. THE RECTAL HALF OF THE PERINEUM (ILLUSTRATIONS OF 

 DISSECTIONS). 



Muscles : 



A. External sphincter. 



B. Corrugator cutis, only part left, 

 c. Internal sphincter. 



D. Levator ani. 



E. Glutens maxiinus. 



Arteries : 

 . Trunk of the pudic artery. 



6. Inferior hgeniorrhoidal, and f. 

 its gluteal branches. 



Nerves : 



1. Inferior htemorrhoidal. 



2. Superficial perineal. 



3. Perineal branch of the fourth 

 sacral. 



4. Perforating cutaneous. 



interims muscle and the fascia covering it. In front it is limited by 

 the triangular ligament (to be afterwards seen) ; and behind are the 

 great sacro-sciatic ligament, and the glutens maximus muscle. 

 Towards the surface it is covered by the teguments, and is overlain 

 in part by the glutens (E) and the sphincter externus (A). 



T'Wx r/, <( 7 nerves in tl: *jxtce. Along the outer wall, contained Pudic ves- 

 in a sheath of fascia, lie the pudic vessels () and the perineal and 

 dorsal divisions of the pudic nerve ; opposite the ischial tuber- 

 osity they are situate about an inch and a half below the surface of 

 the bone, but towards the front of the space they approach to within 



