1032 THE DIGESTIVE SYSTEM. 
side lie the coils of the small bowel and the psoas; to the outer side is the lateral 
wall of the abdomen. Its posterior surface, which is free from peritoneum as a 
rule (Fig. 673), is connected by areolar tissue to the ilacus muscle as far up as 
the crest of the ilium, to the quadratus limborum above this, and finally to the 
lower and outer part of the right kidney. 
In the great majority of cases only the two sides and the anterior surface are 
covered by peritoneum, the posterior surface being destitute of a serous coat (Fig. 
673). Ina small proportion of bodies, however, the ascending colon is provided 
with a complete peritoneal coat and a mesentery, but this latter is so short that it 
admits of but a sheht amount of movement in the cut. 
Like the cecum, the ascending colon is frequently found distended with gas or feeces after 
death, hence in part its large size ‘and prominence as compared with the descending colon, which 
is generally empty. 
Hepatic Flexure (flexura coli dextra).—The hepatic flexure is the bent piece 
of the large intestine between the end of the ee and the beginning of the 
transverse colons (Figs. 688 and 699). 
When the ascending colon, lying on the front of the kidney, reaches the under 
surface of the liver, it t bends—usually acutely, sometimes 0 btusely —forwards and 
to the left, and on reaching the front of the descending duodenum, passes into the 
transverse colon. 
The flexure is placed between the descending duodenum internally and the 
lower thin margin of the liver, or the lateral abdominal wall, externally ; above, 1t 
corresponds to the colic impression on the liver, and behind it rests on the kidney. 
Its peritoneal relations are similar to those of the ascending colon. 
Transverse Colon (colon transversum).—This is the long and arched portion of 
the large intestine which les between the hepatic and splenic flexures. It begins 
where the colon crosses the descending duodenum at the end of the hepatic flexure 
(Fig. 699). From this it runs transversely to the left, and for the first few 
inches is comparatively fixed, being united to the front of the descending duo- 
denum and the head of the pancreas either by a very short mesentery or by areolar 
tissue. Immediately beyond this a long mesentery is developed, which allows the 
colon to hang down in front of the small intestine, at a considerable distance from 
the posterior abdominal wall. Towards its left extremity the mesentery shortens 
again, thus bringing the gut towards the tail of the pancreas (Fig. 688), along 
which it runs upwards into the left hypochondrium, under cover of the stomach, 
as far as the lower end of the spleen, where it passes into the splenic flexure 
(Fig. 687). Its two ends le in the right and left hypochondriae regions respect- 
ively, whilst its middle portion hangs down into the umbilical, or even the 
hypogastric region. 
Its average length is about 19 or 20 inches (47°5 to 50-0 cm.), that 1s more 
than twice the distance, in a direct line, between its two extremities. This 
great length is accounted for by the very irregular course which the bowel 
pursues, — 
Relations.—The greater part of the transverse colon lies behind the great 
omentum, which must consequently be turned upwards in order to expose it. 
Above, it is in contact, from right to left (Fig. 699), with the liver and gall-bladder, 
the stomach, and, near its left end, with the tail of the pancreas and lower end of the 
spleen (Fig. 688). Ln front are placed the omentum and the anterior abdominal 
wall; towards its termination the stomach is likewise in front. Behind, it first hes 
in contact with the descending duodenum and head of the pancreas ; beyond this, 
where it hangs down, the small intestine is placed below and behind, and it is con- 
nected to the posterior abdominal wall (more correctly, to the anterior border of the 
pancreas) by the transverse mesocolon. It is also loosely connected to the stomach 
by the great omentum, which is attached to its anterior surface. The transverse 
mesocolon and the great omentum are described with the peritoneum, p. 1046, 
The transverse colon is completely covered by peritoneum, with the exception 
of the first few inches of its posterior surface, which are often, if not usually, 
uncovered. 
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