ABDOMINAL CAVITY, (ill hUrnall anatomy.) The annexed woodcut exhibits a vertical section of the body intended to show the tho racic and abdominal cavities, from which the viscera have been removed. A simple reference to it and to.fig. 204 will sufficiently explain the form and boundaries of the latter cavity, which have been already fully described in the article ABDOMEN. Our object in the present article is to examine the abdominal cavity as it is brought under the eye of the anatomist, when its contents have been exposed by removing or cutting through the abdominal parietes.
proper epigastric region, covering and con cealing the lesser curvature of the stomach with the gastro-hepatic omentum and the ante rior, or more correctly, the antero-superior surface of the stomach to a variable extent. In this region we likewise see, corresponding pretty nearly to the cartilage of the ninth rib, the fundus of the gall-bladder in some in stances completely covered by the liver, in others projecting beyond it or only covered by a duplicature of serous membrane which fills up a natural notch in the liver. In the epigas It rarely happens that we meet with an in stance in which the abdominal viscera have not been more or less disturbed after death from their natural relations to one another. During life the contractile walls of the ab domen, ever active, maintain such a uniform degree of pressure on the contained organs, that displacements or alterations of positions are very rare occurrences excepting through some preternatural opening in the abdominal parietes. It is advisable to study the positions of the contents of the abdomen in a body re cently dead, and which has not experienced any degree of disturbance.
When the anterior wall of the abdomen has been removed or freely laid open by a crucial incision, the contents of the cavity are brought into view in the following order :— In the right hypochondriac region the liver projects to a slight extent below the inferior border of the chest. This, however, is not to be regarded as the position' of the liver during life ; the descent of that organ from behind the shelter of the ribs is attributable to its gravita tion in consequence of the removal of the support which it obtained from the pressure of the anterior abdominal wall. The liver will thus be found to extend more or less into the trium more or less of the stomach is seen, its greater curvature projecting forwards, having pendent from it the middle portion of the great omentum ; and the left hypochondrium often (especially when the stomach is full) seems to be wholly occupied by the splenic extremity of the stomach, immediately below which there is a portion of the transverse colon, just where it is forming an angle with the descending colon. Sometimes the anterior margin of the
spleen projects before it, and sometimes a still greater portion of the spleen is visible, if that organ be in a state of turgescence. Along the inferior boundary of the epigastric region, and projecting partly into that region and partly into the mnbilical below, the transverse arch of the colon runs with a slight curve concave backwards and downwards. The position of this important portion of the great intestine is always lower in the abdomen of a subject thus opened than it can possibly be during life. In fact, when the abdominal wall is unimpaired and the usual compression is maintained, the stomach and colon must be in very close appo sition with each other, so that it must be diffi cult, if not impossible, to make pressure from without on the one without affecting the other nearly to the same degree. The arch of the colon is loosely covered on its anterior surface by two laminw of peritoneum, which descend from the greater curvature of the stomach and entering into the umbilical region are reflected upwards after a descent as far as the lowest part of that region, forming a curtain which covers the convolutions of the small intestine beneath the transverse arch of the colon. This curtain is the great Omentum or Epiploon, ( Omentum majus,) which, in the natural con dition of the parts during life, there is every reason to believe is closely applied to the an terior surface. of the small intestine ; much variety, however, may be observed as to the extent of its relation to this portion of the intestinal canal, and it is difficult to account for this variety. Thus we sometimes find the in testine uniformly covered by this membrane more or less loaded with fat, descending as low as the upper outlet of the pelvis ; this may be regarded as the normal state in the adult. But at other tifnes we find the omentum so crumpled up or contracted, that the small intestine is completely exposed, and it is only by pulling down the omentum from the arch of the colon towards which it is folded up or crumpled, that we can form an estimate of its extent. Again, in other cases we observe that it is only long enough to descend halfway or a little lower over the surface of the small intes tine. It is said to have less extent in females who have borne many children than in any others; I cannot confirm this statement, inas much as I have not unfrequently seen it of its full dimensions in such subjects. In the na tural state of the parts, then, the whole of the central portion of the umbilical region is oc cupied by the omentum, forming a moveable curtain over the anterior surface of the con volutions of the jejunum and ilium.