928 
towards the anus; the density of the triangular 
ligament of the urethra impedes its passage 
into the pelvis; whilst the loose connection 
between the superficial fascia and the subjacent 
structures in front, the remarkable laxity of the 
dartos, and the continuity of this latter with 
the superficial fascia of the perineum on the 
one hand, and with that of the abdomen on 
the other, are so many circumstances inviting 
the stream to the scrotum, the penis, and the 
walls of the abdomen. The promptest treat- 
ment is demanded to remedy mischief such as 
has been described. A free division of the 
integuments and fascia in the perineum ‘over 
the seat of rupture, for the purpose of giving 
the urine vent and putting a stop to further 
effusion, becomes indispensable, and without 
this measure all others must be unavailing. 
The laxity of the superficial fascia as it 
approaches the scrotum should deter the sur- 
geon from commencing his cutaneous incisions 
in the lateral operation of lithotomy too far 
forwards, lest urinary infiltration should ensue ; 
and the density of the same structure in other 
situations indicates an early incision for the 
release of matter imprisoned beneath it. 
For a description of the posterior or anal 
division of the perineum, including the ischio- 
rectal fosse and the neighbouring fibrous mem- 
branes, the reader is now referred to the arti- 
cle Anus, where all the structures connected 
with the lower extremity of the rectum are 
described in detail. It should be borne in 
mind, however, that some branches of arteries 
(the inferior or external hemorrhoidal) pass 
across the ischio-rectal fosse, entangled in the 
fat which occupies those excavations. The 
inferior hemorrhoidal vessels are usually three 
in number at each side; they derive their origin 
from the internal pudic artery, as it lies be- 
neath the obturator fascia; their destination is 
the lower extremity of the gut and its appen- 
dages, and one of them (the most anterior) 
gains the front of the intestine to anastomose 
with a similar vessel from the opposite side, 
and with branches of the transversalis perinei 
also. The inferior hemorrhoidal vessels are 
remarkably tortuous and rather uncertain in 
their course ; the anterior of them is sometimes 
divided in the lateral or bilateral operations of 
lithotomy, a circumstance which has led to this 
cursory notice of their anatomy. 
When the superficial fascia has been dis- 
placed, many new parts become apparent in the 
genito-urinary division of the perineum; a 
quantity of loose adeps and also a very thin 
glistening fibrous expansion which adheres 
closely to the subjacent muscles and obscures 
’ the dissection, must, however, be carefully re- 
moved before the deeper structures are satis- 
factorily displayed. The central tendinous 
int of the perineum, the superficial perineal 
loodvessels and nerves, the transversalis peri- 
nei artery with its accompanying veins and 
nerves at each side respectively, the urethra 
itself, still however obscured by the accelera- 
tores urine muscles, the crura penis, each 
partly enveloped by the erector penis muscle, the 
PERINEUM. . 
transversi perinei muscles, and two small trian- 
gular spaces bounded by muscles and placed — 
one at either side of the urethral prominence, 
are the principal objects which come into view. 
The central tendinous point of the perineum — 
is situated in the middle line, equidistant from — 
the anus and the bulb of the urethra. It is a 
common point of insertion to many muscles; 
thus the superficial sphincter of the anus can 
be fairly traced to this spot, and so can many 
fibres of the acceleratores urine, the 5 
perinei, the levatores ani, and Wilson’s mus- 
cles. Here muscular fibres from opposite sides 
of the perineum become blended with eac 
other; here, too, those from before and those 
from behind are intermixed, and some even 
descend from within the pelvis to identifi 
themselves in this place with others which are 
subcutaneous. “* 
The superficial perineal artery (the perines 
artery of some anatomists), though not a large 
vessel, yet takes a lengthened and very regular 
course. Its origin is from the internal pudie 
artery at some little distance behind the trans- 
versus perinei muscle, whilst the parent trum 
is still under cover of the obturator fascia; 
immediately pierces that membrane, and like 
wise very generally passes through the base o 
the triangular ligament of the urethra. T 
artery next curves around the transversus f 
nei muscle lying on its superficial surface an 
running across its fibres. The vessel then in 
clines forwards and inwards through the tria 
gular interval between the accelerator uri 
and the erector penis muscles, until at lengt 
reaches the scrotum, and assuming the nam 
of “the arteria septi,” it terminates in a fre 
anastomosis with the other arteries supplyit 
the envelopes of the testicles. The superfic 
perineal artery lies deep posteriorly, but 
position becomes very superficial as it | 
roaches the scrotum; its branches are dis 
uted freely to the muscles and integuame 
and they likewise anastomose internally wi 
branches from the corresponding artery of th 
opposite side, and externally with superfic 
branches from the thigh. Two veins acc 
pany this artery; they are frequently di 
and tortuous in front, and in certain disi 
conditions of the testicle or its coverings 1 
sometimes form a complicated net-work it 
scrotum. al 
The inferior or superficial division of 
pudic nerve (“ the perineal nerve” of 
authors) follows pretty nearly the cot 
these vessels; like the artery, it is destine 
the scrotum, where it terminates by s 
long and very fine branches, after supply: 
its progress numerous twigs to the trans 
perinei, accelerator urine, levator 
erector penis muscles. One very 
branch of this nerve (the bulbo-ureth 
Cruveilhier) may be traced fairly into thi 
whilst another (the external perineal 
same anatomist) runs superficial 
lateral part of the region, reinforcing 
anastomosing with the perineal ecutan 
branch of the lesser sciatic nerve. 
a 
a 
