MUSCLES 47 



the vena azygos minor. The cord of the sympathetic per- 

 forates the outer part of the crus. 



PERINEAL REGION. 



Superficial Fascia. In the anterior half of the perineum this 

 consists of two layers, the superficial fatty and the deep layer 

 fibrous and well marked (fascia of Colles) : the latter is attached 

 to rami of pubes and ischium, and from ischial tuberosity to 

 central point of perineum ; here it joins the triangular liga- 

 ment, by turning round the transversus perinei. It is con- 

 tinuous in front with the dartos. and from its deep surface there 

 is a septum passing forwards to scrotum in the middle line. 



Triangular Ligament of the Urethra, or Deep Perineal Fascia, 

 consists of two layers. The anterior layer is attached to the 

 symphysis and to rami of pubes and ischium on each side, 

 and joins the superficial fascia where this curves over the 

 transversus perinei. About an inch below the symphysis it is 

 perforated by the urethra, and above this by the dorsal vein 

 of the penis, and on either side of this opening the dorsal artery 

 and nerve of penis are transmitted. The posterior layer 

 consists of two lateral portions separated in the median line 

 by the urethra, and continuous with the recto-vesical fascia 

 in the middle line, which here invests the prostate ; exter- 

 nally it joins the obturator fascia on the pubic and ischial 

 rami, and is really the subpubic part of the parietal pelvic 

 fascia. 



Parts between the two layers of the triangular ligament. Sub- 

 pubic ligament, dorsal vein of penis, membranous part of 

 urethra, compressor urethrae. Cowper's glands and ducts, 

 internal pudic arteries giving off branches to bulb, to glands 

 of Cowper, and the artery to corpus cavernosum, and the 

 dorsal nerves of penis. 



THE PELVIC FASCIA. Lines muscles of pelvis and forms 

 f oor of outlet of pelvis. Consists of parietal and visceral 

 layers. 



Parietal Layer, (a) The Obturator Fascia. Covers inner 

 surface of obturator internus. It is attached above to ilio- 

 pectineal line, to oblique line on posterior surface of body of 

 pubes from symphysis to upper part of thyroid foramen. 

 Posteriorly it is attached to the anterior edge of the sacro- 

 sciatic notch and large sacro-sciatic ligament, whilst below it 

 is attached to the rami of pubis and ischium, and in front in 

 the subpubic angle is continuous with the posterior layer of 

 the triangular ligament. At th^ top of the thyroid foramen 



