1916 



H I'M AN ANATOMY. 



ischial tuberositiesand rami, and the pubic rami laterally (Fig 1627). It is divided 

 into two lateral symmetrical halves by a dense cutaneous ridge, the raphe, across 

 which, as it represents the junction of the two foetal halves of the perineum, no blood- 

 vessels pan from one side to the other; and into two Asymmetrical antero-postenor 

 triangular portions by an imaginary transverse line drawn between the anterior 

 borders of the ischial tuberosities and running in front of the anus. The posterior 

 of these two divisions the portion of the outlet of the pelvis which contains the 

 rectum and anus is the rectal triangle (anal perineum). Its practical relations have 

 been sufficiently dealt with in the article on the rectum and anus (page 1693)- . 



The anterior division, the uro-genital triangle (urethral perineum;, has for its 

 deep boundaries : posteriorly the deep layer of the superficial fascia (fascia of Colles) 

 as it passes behind the transverse perineal muscles to become continuous with the 

 inferior layer of the triangular ligament (page 563); laterally the rami of the pubes 



-Position of 

 urethra 



Colles's fascia 



Sphincter ani 



externus 

 .Tuber ischii 



Int. imdic artery. 

 Pudic nerve- 

 Anal fascia - 

 Inferior hemor-f- 

 rhoidal artery \ . 

 Inferior hemor-/ 

 rhoidal nerves) . 





Tip of coccyx 



Dissection of potinrutn, showing superficial and hemorrhoidal bnunhcs of internal pudic 

 artery and of pudic nerves on right side ; Colles's fascia exposed on left. 



and ischia ; anteriorly the pubic arch. Over the uro-genital triangle the superficial 

 fascia is si parable into two distinct layers, the superficial and the deep. The super- 

 ficial layer contains a considerable amount of fat, and is continuous with the corre- 

 s|>< >n<liii^ layer <>\rr the thighs and buttocks and with the masses of fatty tissue that 

 till tin- ischii i-rrctal f<>ss;r. The deep layer, or fascia of Colles, is membranous and 

 fn > from fat, and is not only applied closely to the lower edges of the transverse 

 perinea! muscle* and attached to the base of the inferior layer of the triangular liga- 

 ment. 1'tit is also attached to the external margin of the rami of the pubis and ischium. 

 Anteriorly it is continuous with the deep layer of superficial fascia of the scrotum 

 (daitosi, penis, and spermatic cords, and with the fascia of Scarpa (page 515) 

 on tlu- front of the abdomen. When it is divided, a definite space, the superficial 

 f>,-> hit-til intfrsfxiif, is opened, which is bounded below by Colles's fascia, above by 

 th<- inferior layer of the triangular ligament, laterally by the attachments of the fascia 



