1230 SURFACE AND SURGICAL ANATOMY. 
The great vessels upon the posterior abdominal wall, along with the adjacent 
lymphatic vessels and glands, he in the extra- peritoneal fat, and therefore within 
the general fascial env elope of the abdomen. Abscesses originating from the 
retro- peritoneal lymphatic glands are, therefore, like perinephritic abscesses, extra- 
peritoneal, but mtra- fascial ; abscesses of spinal origin, Whether lumbar, iliac, or 
psoas, are, on the other hand, extra-fascial. Abscesses connected with the vermi- , 
form appendix are primarily intra-peritoneal; occasionally they ulcerate through — 
the parietal peritoneum and burrow in the extra-peritoneal fat. 
THE MALE PERINEUM. 
The male perineum is a heart-shaped space the osseous boundaries of which are 
the same as those which form the outlet of the pelvis. A line drawn transversely 
across the perineum between the anterior part of the tuberosities crosses the middle 
line immediately in front of the anus, and divides the space into an anterior or 
urogenital triangle and a posterior or rectal triangle. The urogenital triangle i 
subdivided into a superficial and deep compartment by the triangular ligament ; 
the superficial compartment is the root of the penis, which gives rise to a ie 
tudinal fulness upon the surface. Anteriorly, the surface of the urogenital triangle 
is continued on to the scrotum, whilst laterally a distinct groove separates it from 
the inner surface of the thighs. The central point of the perineum (common tendon 
of the perineal muscles) is continuous with the centre of the base of the triangular 
ligament, and lies a finger’s breadth in front of the anus. Immediately 1 in front of 
it, and about 1 in. from the centre of the anus, is the posterior edge of the bulb 
of the corpus spongiosum. The superficial compartment of the urogenital triangle 
is bounded below by the perineal fascia of Colles, which is attached posteriorly to the 
base of the triangular ligament, and laterally to the margins of the pubic arch. 
Anteriorly, the fascia of Colles passes on to the scrotum, the penis, and sper- 
matic cord, to become continuous with the fascia of Scarpa upon the front of the 
abdomen. 
When the urethra is ruptured below the anterior layer of the triangular liga- 
ment, the course of infiltration of extravasated urine is determined by these attach- 
ments; at first, therefore, the urine is confined within this compartment, but 
eradually travels forwards under the fascia of Colles on to the lower part of the 
anterior abdominal wall; it is prevented from passing down the front of the thigh 
by the attachment of Scarpa’s fascia to the fascia lata, a little below Poupart’s 
ligament. 
The deep compartment of the urogenital division of the permeum corresponds to 
the interval between the triangular ligament proper and the parietal layer of the 
pelvic fascia (the so-called superior or deep layer of the triangular hgament). 
The most important structures which this compartment contains are the membranous 
portion of the urethra, Cowper’s glands, the internal pudic vessels, and the artery 
to the bulb. 
The membranous part of the urethra lies 1 in. behind the lower border of the 
pubic symphysis. When this division of the urethra is ruptured, the extravasated 
urine, after filling the deep compartment, may reach the superficial compartment. 
by bursting through the triangular od where the vessels pierce it; or 1t may 
penetrate the parietal layer of the pelvic fascia, infiltrate the perivesic: al connective 
tissue and the space of ‘Retzius, and ultimately ascend in the anterior abdominal 
wall between the fascia transversalis and the parietal peritoneum. 
Cowper’s glands, which lie immediately behind the membranous urethra, are 
overlapped by the bulb of the urethra, from which they are separated by the tri- 
angular ligament. The internal pudic artery lies just within the margin of the 
pubic arch. The artery to the bulb runs transversely inwards } in. above the base 
of the triangular ligament, 7.e. above the level of a line drawn from the front of the 
tuberosities to the central point of the perineum. 
The male urethra measures about 8 in. from the external to the internal 
meatus; the narrowest portion is at the external meatus; a second narrowing 
occurs at the triangular hgament. It is behind these constrictions that a calculus 
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