THE FERLWEi'M PROPER 1065 



is joined by the sloping inner wall where the ischio-rectal fascia ji>ins the oljturator 

 fascia, so that the space is angular y\ in outline in frontal section. ,So far all 

 anatomists are agreed, but the remaining boundaries rcijuire further investigation. 



If the linger be introduced into the anterior part of the fossa, it will meet the line 

 of junction of the triangular ligaments with the fascia of Colics; and above this will 

 be found an anterior recess of considerable size extending forward nearly as far as 

 the symi)hysis, between the superior triangular ligament and the under surface of the 

 levator ani, and limited internally by the prostate and pubo-prostatic ligaments, and 

 externally by the })ubic and ischial rami. At the l)ack part of the space will l)e felt 

 the border of the great sacro-sciatic ligament, and above this a posterior recess 

 running backwards for a variable distance towards the sacrum. Both of tlusr deep 

 extensions are lined by the ischio-rectal and obturator fasciae, and tilled with fat and 

 connective tissue. The ischio-rectal fossa must then be described as an anvil- or 

 T-shaped cavity with anterior and jjosterior recesses running the one above the 

 perimeal ledge, the other above the sacro-sciatic ligaments. 



Contents. — The ischio-rectal fossa is filled with loose adipose tissue continuous 

 with the subcutaneous fat of the buttock, and traversed from Avithout inwards l>y 

 the inferior hiemorrhoidal In-anches of the pudic artery, and by the associated veins 

 and some tAvigs of the internal pudic nerve passing to the spliincter ani and adjacent 

 skin and mucous meml)rane. 



The veins are usually somewhat dilated near the anal margin, and when 

 morl)idly enlarged constitute the condition known as haemorrhoids or piles. Near 

 tiie posterior border of the triangular ligaments the pudic vessels and nerves give 

 off their superficial perinieal branches, which almost immediately enter the sujjer- 

 ficial jterina^al interspace. 



A small branch of the fourth sacral nerve may be seen turning over the back of 

 the space to reach the anal integument. 



THE PERIX^UM PROPER 



The perinaeum proper (figs. 647, 652), considered apart from the portion of the 

 common integument wliich covers it in, is a curious triangular ledge of tissue 

 stretched almost horizontally across the angular interval between the two ischio- 

 pubic rami. It is pierced Ijy the urethra (and also by the vagina in the female), 

 and comprises three strong fascite which enclose within two interfascial spaces the 

 root of the i)enis with the muscles appended to it, the compressor urethra? muscle, 

 Cowper's glands, and a number of vessels and nerves. Above it lie the prostate 

 and levatores ani with their fascia^, and the anterior recess of each ischio-rectal 

 fossa. 



The perinai'al integument has already been descriljcd. On removal of the skin 

 with its dartos and the superficial layers of superficial fascia, a deeper ])lane of 

 fascia will be exposed, connected firmly with the ischio-pubic rami. This is the 

 fascia of Colles (the deep layer of the superficial perinteal fascia), the most su])er- 

 ficial of the tliree true i>erina?al fascia\ 



The fascia of Colles is a fibrous lamina of considerable strength. It is attached 

 on each side to the lower margin of the ischio-pubic ramus and to the ischial 

 tuberosity; behind, it turns around the posterior border of the sujierficial transversus 

 l»erina'i muscle to fuse with the posterior borders of the sujierficial and deeji tri- 

 angular ligaments and form the free border of the ' perina'al ledge ' ; anteriorly, it 

 becomes continuous with the external fascial investment of the scrotum and the 

 fascial covering of the ])enis. 



It is l)etween this layer and the inferi(^r triangular ligament that extravasation 

 of urine is esi)ecially prone to occur in ru]>ture of the urethra. From its connec- 

 tions it will be seen that the extension of the fluid would l»e arrested ))osteriorly 

 and laterally by the connection of the fascia of Colles with the triangular ligaments 

 and with the ischio-pul)ic rami; but it spreads freely beneath the integuments of 

 the scrotum and of the penis as far as the neck of the glans, and to the surface of 

 the abdomen. On the trunk, it may run in an upward direction even to the axilla, 

 but it is prevented from descending below the groin by the connection of the 



