88 OUTLINES OF ANATOMY. 



In the urethral triangle the superficial fascia consists of two well-marked layers, a superficial layer and 

 a deeper layer, or fascia of Colles. The deep layer, or fascia of Colles, turns around the posterior 

 border of the superficial transverse perinaei muscles, and blends with the posterior border of the tri- 

 angular ligament, not extending over the rectal triangle. The superficial layer of the fascia should 

 now be removed, carefully preserving the deeper layer, or fascia of Colles. In the rectal triangle the 

 external sphincter ani and the superficial vessels and nerves will be exposed. 



Sphincter ani externus, action, 1097-8. (1074) 



Dissect out the fat from the ischio-rectal fossae, and expose the haemorrhoidal vessels and nerves. The 

 greatest care should be exercised not to injure the fascial boundaries of the ischio-rectal fossae. 



Ischio-rectal fossae, contents, 1102-3. C I0 97) 



The obturator fascia, 1098-9; Fig. 648. (1075) 

 Lower or ischio-rectal segment. 



Ischio-rectal or anal fascia, 1102; Fig. 648. (1077-9) 

 External or inferior hsemorrhoidal branches, 609. (597) 

 Inferior haemorrhoidal nerve, 858. (838) 

 Perinaeal branch of the fourth sacral nerve, 853. (834) 

 Superficial lymphatics of the perinseum, 700. (685) 

 Perinaeum proper, fascia of Colles, 1103. (1080) 



Fascia of Colles, 1103-4. (1080-1) 



Demonstrate the attachments of the fascia of Colles, and the extent and outline of the superficial peri- 

 naeal interspace. To do this, make a short incision through the fascia, a little to one side of the median 

 line; introduce the point of the blowpipe, and drive air into the space; the attachments of the fascia 

 and the outline of the space will be rendered distinct. 



Divide the fascia of Colles and reflect it, exposing the structures in the superficial interspace. Fig. 

 370 A, P. 609, and Fig. 371. (598) 



Superficial perinseal interspace, 1104-5. (1081) 

 Contents : (i) The crura, 1070. (1047) 



The ischio-cavernosus, 1072. (1049) 

 Compressor vena? dorsalis. 



(2) The bulb, 1071-2. (1049) 



Expose the bulbo-cavernosus; study its structure and relations, then divide 

 the muscle near the median line and reflect it from the surface of the bulb. 



Bulbo cavernosi, 1072. (1049) 



(3) Superficial transversi perinsei, 1072. (1049-50) 



(4) Arteries of the corpora cavernosa. 

 Dorsal arteries of the penis. 

 Veins. Lymphatics. 



Artery of the corpus cavernosum (crus), 611. (599) 

 Dorsal artery of the penis, 611. (599) 

 (5)' Dorsal nerves of the penis, 858. (837) 

 (6) Superficial perinseal vessels and nerves. 



Superficial perinseal branch, 609-10. (597-8) 



Transverse perinseal artery. 



Posterior or external superficial perinseal nerve, 858. 

 (838) 

 Anterior or internal superficial perinseal nerve, 858. 



(838) 



The long pudendal nerve may be traced to advantage at this time. Follow 

 the nerve back to its superficial origin and trace the branches forward. 



The long pudendal nerve, 857. (837) 



Remove the muscles from the superficial perinseal interspace and expose the inferior triangular 

 ligament. 



Inferior triangular ligament, 1105. (1081-2) 



Divide and turn off the inferior triangular ligament, exposing the deep perinasal interspace. See Fig. 

 370, P. 609 (left side). (598) 



