THE MALE PERINEUM. ok 
is lable to become impacted. The most dependent part of the urethra is the 
bulbous portion, and it is in this situation that an organic stricture is most 
frequently met with. The membranous portion of the urethra, situated between 
the two layers of the triangular hgament, is surrounded by the compressor urethrie 
muscle, which, when thrown into spasm, may firmly grip an instrument as it 1s 
passed into the bladder. Rupture of the wrethra trom a fall on the perineum 
generally involves the bulbous portion. <A false passage made during the passage 
of an instrument generally traverses the floor of the urethra at the trianeul: iv liga- 
ment; to prevent this the point of the instrument should always he directed 
upwards, and the handle at the same time depressed as soon as the instrument is felt 
to encounter the resistance of the triangular ligament. When the prostate is hyper- 
trophied the prostatic portion of the urethra is elongated, and the internal meatus 
may look directly forwards, while if the lateral lobes are unequally enlarged it 
may deviate laterally. Patients with prostatic hypertrophy are seldom able to 
completely empty the bladder, on account of the dependent well which exists 
below and behind the prostate. 
The epididymis, which can be felt behind the testicle as an elongated curved 
body apphed vertically to its posterior surface, is especially involved in gonorrhceal 
and tubercular infections of the testicle. Occupying the posterior part of the 
spermatic cord is the vas deferens, which, when grasped between the finger and 
thumb, feels like a piece of whip-cord. The spermatic veins form a plexus in the 
substance of the cord, known as the pampiniform plexus; a varicose condition of 
these veins gives rise to the condition known as varicocele. In operating for 
varicocele the veins are reached | oy dividing in succession all the coverings of the 
cord; the deepest covering, viz. the infundibuliform fascia, derived from the fascia 
transversalis, forms a we el-marked fibrous env elope which immediately surrounds 
the veins and other constituents of the cord. Besides the spermatic artery, the 
testicle receives its blood supply from the artery accompanying the vas deferens 
and from the cremasteric branch of the deep epigastric. 
The marked swelling which attends wdema und hematoma of the scrotum is due 
to the loose and delicate character of the cellular tissue which occupies the space 
between the dartos muscle and the subjacent membrane derived from the inter- 
columnar fascia. ‘ 
The anus is situated in the rectal division of the permeum about 14 in. in front 
of and below the tip of the cocecyx. The skin around the orifice is pigmented and 
thrown into radiating folds. The painful hnear crack or ulcer, known as jfisswre of 
the anus, generally occupies one of the furrows at the posterior margin of the anus. 
The skin of the anus is provided with large sebaceous and sweat elands, which are 
occasionally the site of small and very painful anal abscesses. 
On making a rectal examination it will be observed that the finger, before it 
reaches the cavity of the rectum, traverses the narrow or sphincteric portion of the 
rectum, appropriately named by Symington the anal canal. This canal, which is 
directed from below upwards and forwards, extends from the anal orifice to the 
ampulla of the rectum, is about 1 in. in length; its upper end is on a level with 
the inner borders of the pubo-rectal portions of the levatores ani. 
External hemorrhoids are developed from the anal folds situated outside the 
white line corresponding to the muco-cutaneous junction; infernal piles are 
developed from the veins of the mucosa at the upper part of the anal canal. 
In the upper half of the anal canal are the valves of Morgagni. According to 
Ball, fissure of the anus is generally caused by the tearing downwards of one of the 
posterior valves during the passage of a scybalous mass. 
According to Birminghain, the pubo-coccygeal fibres of the levator ani close the 
upper part of the anal canal, whilst the external sphincter closes the remaining 
part. The internal sphincter, according to the same author, acts probably as a 
detrusor, its use being to empty the anal canal completely after the passage of 
each faecal mass. 
The apex of the ischio-rectal fossa, formed by the attachment of the anal fascia 
to the obturator portion of the parietal pelvic fascia, is directed upwards towards 
the pelvis, and lies 24 in. from the surface. The inner wall of the fossa is 
