PERINEUM. 
fan-shaped, appearing expanded at the urethra 
and contracted at their origin from the bone, 
and they are believed to have the power of 
compressing the urethra so as to close the canal. 
Notwithstanding the accurate descriptions of 
Mr. Guthrie, many excellent anatomists have 
failed to demonstrate the exact arrangement of 
fleshy fibres which he has remarked, but the 
majority incline to the opinion that the peculiar 
reddish material in question is of a muscular 
nature. 
The arteries of the bulb (one at either side) 
spring from the internal pudic after those ves- 
sels have arrived at the triangular ligament of 
the urethra, and whilst they are overlapped by 
the crura penis. Interposed between the la- 
mine, and situated about a quarter of an inch 
above the base of the triangular ligament, the 
artery of the bulb runs nearly transversely in- 
wards, and near the urethra divides into two 
branches, of which one is small and destined for 
Cowper’s gland, whilst the other is of large 
size and perforates the bulb to supply the 
corpus spongiosum urethre. The arteries of 
the bulb are of considerable magnitude, parti- 
cularly after puberty, so that they bleed pro- 
fusely when wounded ; they retract between the 
layers of the triangular ligament when divided, 
and this added to the narrowness of the peri- 
neum in front, and to the distance from the 
surface at which they are placed, renders it diffi- 
cult for the surgeon to secure their cut extremi- 
ties or otherwise to control their hemorrhage. 
The consequences of such an accident may 
prove speedily fatal; extreme care must there- 
fore be taken to protect these vessels from the 
knife during lithotomy. 
The artery of the bulb is endangered in the 
second period of the lateral operation whilst the 
surgeon cuts into the membranous portion of 
the urethra to lay bare the groove of the staff. 
The knife should be introduced into the urethra 
behind the bulb, and below and behind the 
course of the artery, and little or none of the 
triangular ligament except the posterior lamina 
where it invests the membranous portion of the 
urethra, should be divided in this incision, for 
the vessel requiring protection lies about one 
quarter of an inch above the base of the liga- 
ment, and therefore none but the very lowest 
fibres of that structure can be cut with impu- 
nity ; in short the incision must be made into 
_ the membranous portion of the urethra as it 
lies behind the triangular ligament, and the 
_ bulb must be studiously avoided. Irregularities 
_ in the direction of these arteries calculated to em- 
_ barrass the operating surgeon are occasionally 
encountered ; arising sometimes prematurely 
from the pudic, they ascend very obliquely to 
_ the bulb; and again, although given off from 
_ the pudic at the usual place, they now and then 
take a curved course to their destination, the 
‘convexity of the curvature looking downwards 
-and backwards; when either of these varieties 
occurs, the vessels in question run much closer 
‘to the base of the triangular ligament than 
“usual, and are therefore imminently endangered 
‘in lithotomy. 
_ The internal pudic arteries in their third 
931 
stage belong to the perineum. This stage com- 
mences where the vessel enters the pelvis at the 
lesser sciatic notch, and ends at the ramus of 
the pubis, where it divides into its terminating 
branches. Posteriorly the trunk of the internal 
pudic is (strictly speaking) placed outside the 
precincts of the perineum, being separated from 
the ischio-rectal fossa by the obturator fascia, 
but it runs so close to that part of the region, 
and sends so many of its branches through the 
intermediate partition to lose themselves in pe- 
rineo, that its description may be here legiti- 
mately given. At the commencement of its 
third stage, the internal pudic is interposed he- 
tween the obturator fascia and the obturator 
internus muscle, the muscle separating it from 
the bone, whilst the falciform process of the 
great sciatic ligament covers the artery infe- 
riorly : in this situation it les at a great depth 
from the surface, being upwards of an inch 
above the level of the tuber ischii, and at least 
two inches and a-half distant from the integu- 
ment; it here also describes a slight curve in- 
clining upwards, forwards, and inwards, towards 
the edge of the ramus of the ischium. In the 
latter part of its third stage the internal pudic 
artery insinuates itself between the lamine of 
the triangular ligament, and after continuing 
thus for some distance it at length perforates 
the superficial layer, places itself between the 
crus penis and the ramus of the pubis, and there 
finally divides into the artery of the crus and 
the dorsal artery of the penis. 
On entering the pelvis the pudic arteries of 
opposite sides are widely separated from each 
other, but in the neighbourhood of the pubis 
they gradually converge until their ultimate 
branches meet on the dorsum of the penis ; their 
position likewise becomes more and more su- 
perticial as they proceed. 
In the early part of its third stage the pudie 
artery is accompanied by the trunk of the inter- 
nal pudic nerve, and afterwards for a short dis- 
tance by both the branches of that nerve; but 
the deeper of the two (viz. the dorsalis penis) 
alone continues in relation with the artery in 
the latter part of its course. ‘Two veins accom- 
pany the artery throughout. 
The. position of the internal pudic vessels 
exposes them to injury in the lateral operation 
of lithotomy ; but if their relations be considered 
it will appear that the danger of hemorrhage 
from this source has been much exaggerated. 
The falciform process of the great sciatic liga- 
ment, the crus penis, the projecting edges of 
the bones, and the obturator fascia afford these 
vessels so much protection from below that the 
operator seldom wounds them in cutting into 
the bladder, nor is such an injury possible un- 
less the edge of the knife be lateralized to an 
extreme degree ; but if the knife be carelessly 
withdrawn from the bladder, they certainly 
incur considerable risk, for in that step of the 
operation a layer of fibrous membrane alone 
protects the vessels, and the convex edge of the 
instrument, if directed unduly outwards, might 
readily enough divide them. When such an 
accident has occurred, all attempts to tie the 
bleeding artery in the ordinary manner have 
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