938, 
It seems as though the gall-duct in gaining 
the shortest route from the liver to the duode- 
num had carried out the superjacent peritoneum 
from the cardia and lesser gastric curvature into 
a fold, as far out as the position of the straightest 
line from the porta to the pylorus; that this 
fold would have projected in the middle line, 
but that the enlargement of the right lobe of the 
liver displaced its posterior part with the cardia 
to the left, whilst the duodenum being brought 
into adhesion with the posterior abdominal 
walls displaced its anterior part to the right, 
and that both displacements have resulted in 
an almost transverse instead of an antero-poste- 
rior horizontal direction. In many vertebrate 
animals, especially those below the class Mam- 
malia, the duodenum is not adherent to the 
posterior abdomina! parietes, and the pylorus as 
well as the cardia is frequently in the middle 
line, whilst the two lobes of the liver are of 
pretty equal transverse extent; in such cases 
the lesser omentum extends antero-posteriorly 
in the middle line, (figs. 490, 491,) and this, 
we consider, is its typical position. This point 
will be more fully considered when we come to 
a particular description of the omenta; at pre- 
sent we are endeavouring to demonstrate the 
continuity, merely, of the peritoneum through- 
out: it is the existence of the omenta, or rather 
their distorted position in the human subject, 
that renders this demonstration so difficult. 
It is necessary at this stage of our description 
to study the peritoneal sheet, or bag, with two 
free surfaces, called the greater omentum. On 
making an incision, as above, through the abdo- 
minal parietes, the liver and stomach are at 
once brought into view; but the small intes- 
tines are concealed by the great omentum co- 
vering them in front. It is a membraniform 
apron, having plentiful reticulations of vessels, 
and often loaded with fat, especially near the 
vessels. Viewing it undisturbed it appears to 
be pendent from the greater curvature of the 
stomach, and to have a free inferior border 
touching, usually, the pelvic region; but on 
lifting it up and looking at its posterior aspect, 
it is seen to be attached also to the transverse 
portion of the colon, which at once informs one 
that it is double. The fact of its being double, 
however, may be much more strikingly demon- 
strated in the following manner. If a catheter 
be held in the foramen of Winslow, and air be 
blown through it, the great omentum (provided 
there be no abnormal breach of continuity or 
adhesion in it) will become inflated like a great 
bladder; the inflation extending, not only 
downwards below the greater curve of the sto- 
mach, but to the left beyond its fundus, and 
also to the lesser omentum. The cavity so in- 
flated is called the sac of the omentum, or the 
posterior cavity of the peritoneum, and the fo- 
ramen of Winslow is the orifice that leads to this 
sac—the neck that connects together the ante- 
rior and posterior cavities of the peritoneum, 
making them one. 
The foramen of Winslow is not generally big 
enough to admit more than one or two fingers 
to be passed through it; but an incision being 
made through the lesser omentum, the hand 
PERITONEUM. 
may be introduced into the omental sac and 
passed downwards behind the stomach and in 
front of the transverse colon, until it reaches the 
lowermost extent of the great omentum, or bot- 
tom of the great omental pouch ; it will thus be 
between the two layers of what we considered 
like a double apron, but which, rather, is a 
uch, The hand may now be carried in either 
teral direction until it is arrested by the sides 
of the pouch, which correspond, on the right 
with the point where the colon crosses'the duo- 
denum, and on the left with the point where 
the colon, from being transverse, becomes de- 
scending,—that is to say, the sides of the pouch 
hang down from these points. Above the latter 
a the hand may be carried towards the left, 
yond the fundus of the stomach and some- 
i behind the spleen, where it will ber 
y an attachment to the posterior pari 
line of which extends fron the carda to theleft 
ge of the colon. Sa 
here is, therefore, a great pouch of perito- 
neum, the inside and outside of which are both 
free; and consequently it has an internal or 
lining layer and an external layer; we will 
presently show how these are continuous with 
each other and with the peritoneal investments 
of surrounding parts. e left side of the 
mouth of this pouch is carried up into a long 
corner reaching the cardia ; its continuous line 
of attachment extends from the cardia along the 
greater curvature of the stomach to the pylorus; . 
then along a small extent of the duodenum till 
it reaches the transverse colon; next along the 
transverse colon to its left bend, and thence 
along on the posterior abdominal parietes of the 
left hypochondriac region, or rather over the 
left kidney, to the cardia whence we started. 
The spleen is sessile upon the external surface 
of this bag to the left of the fundus of the sto- 
mach. That portion of it which intervenes 
between the stomach and colon is called the 
great omentum, and that portion which is 
situated to the left of the fundus of the stomach — 
is called the splenic omentum. a 
We may now return to our demonstration of 
the continuity of the peritoneum by tracing it 
free surface as before. The two surfaces o1 
layers of the lesser omentum were seen to 
continuous around the vessels enclosed in its 
free right border, at the foramen of Winslow. 
These two layers, as yet adherent, separate 2 
the lesser gastric curvature, invest the stomacl 
—one behind and the other in the front—met 
again, and again adhere along the fundus al 
greater curvature, forming a sheet with two fit 
surfaces, which to the right extends to the sf 
and abdominal parietes, and downwards te 
transverse colon ; that part of it, however, wi 
intervenes between the stomach and co 
bagged out or excessively widened so as, 
ordinary circumstances, to hang down in 
pouch as low as the. pelvis. Having reael 
the front of the transverse colon, the layers 
separate to invest it—one above and the ol 
below—meet again on its posterior aspect, and 
again adhering together form the transverse 
socolon, which extends from the colo 
posterior abdominal parietes, where having: 
