SUPERFICIAL FASCIA OF ANTERIOR HALF. 243 



raids in a sheath of the obturator fascia, lying below the pudic 

 ?ls. At the fore part of the ischio-rectal fossa it divides into 

 cutaneous, muscular, and genital offsets. Its two cutaneous branches 

 (superficial perineal) may be seen on the right side, where they lie 

 fur a short distance in the fat of the hollow. 



The dorsal nerve of the penis accompanies the pudic artery along and dorsal 

 the outer side of the ischio-rectal fossa to the fore part of the peri- Jem's. 

 neum. It is also enclosed in the obturator fascia, but is deeper than 

 the blood-vessels. 



The PERINEAL BRANCH OF THE FOURTH SACRAL NERVE reaches Offset of 



the ischio-rectal fossa between the levator ani and coccygeus, or by nerve. 

 piercing one of these muscles, near the coccyx, and ends by supplying 



the external sphincter. 



The PERFORATING CUTANEOUS NERVE is an offset from the lowest Perforating 



part of the sacral plexus, and is named from its piercing the great n erve! l 

 sacro-sciatic ligament in its course to the perineum. Turning up- 

 wards round the lower edge of the glutens maximus, its branches 

 are distributed to the skin of the inner and lower part of the gluteal 

 region. 



ANTERIOR HALF OF THE PERINEAL SPACE. 



In the anterior part of the perineal space are lodged the crura of Urethral 

 the penis, and the tube of the urethra as it courses from the interior 

 of the pelvis to the surface of the body. Placed midway between the and general 



bones, the urethra is supported by the triangular ligament of the 

 perineum, and by its union with the penis. 



Muscles are collected around the urethra and the crura of the penis : 

 most of these are superficial to, but one is within the triangular 

 ligament. 



The vessels and nerves lie along the outer side, as in the posterior 

 half, and send offsets inwards. 



Dissection (figs. 92 and .93). To raise the skin from the anterior ^ion* to 

 half of the perineum, a transverse cut is to be made at the back of the skin. 

 scrotum, and is to be continued for a short distance (two inches) on 

 each thigh. A second incision along the middle line from the one 

 already made will allow the flap of skin to be reflected outwards. 



After the removal of the skin, the superficial fascia which covers Blow up 

 the front of the perineal space should be blown up by means of a fSSa, and 

 pipe attached to an ordinary cycle inflating pump or a pair of bellows, reflec * it- 

 introduced beneath it posteriorly. Each side should be gently 

 inflated separately to demonstrate the fact that there is a partition 

 along the middle line. It will be seen that the air does not pass 

 from the perineal space into the thigh, showing that the fascia is 

 attached to the bony margins of the space. 



The student is next to cut through the superficial fascia on the left 

 side of the scrotum to the ischio-rectal fossa; and after reflecting 

 it, and removing loose fatty tissue, its line of attachment to the bone 

 externally, and to the triangular ligament posteriorly, will be brought 

 into view. The septum along the middle line should be also defined. 



R 2 



