The Belly, from abdo, to hide; as its contents lie hid in it. The last syllable is only a termination; as from lego, legumen. It is also called Imus Venter. Alvus. Gaster. Katocalia. Faesius calls it Dertron; Nedys; and the viscera contained within, Nedya.
The body is generally divided into three cavities, called, by anatomists, venters: viz. the head, or upper venter; the breast, or middle venter; and the abdomen, or lower venter.
The belly is divided, on its outer surface, into four regions, called the epigastric, the umbilical, the hypogastric, and the lumbar. See Epigastrium, Umbili-calis regio, Hypogastrium, and Lumbaris regio. These are all contained betwixt the circumference of the false ribs, and the bottom of the ossa innomi-nata.
The belly is separated from the breast externally, by the extremities of the ribs, and internally by the diaphragm; and it is terminated below by the musculi le-vatores ani.
The bottom of the belly, named Neiara, on its fore part, is called the pudenda; and on its back part, the buttocks, and anus; and underneath, betwixt the anus and the pubes, the perinaeum; indeed, the name of pe-rinaeum is given to the whole space from the os coccy-gis: that part which lies between the anus and pubes is distinguished, according to Dr. Hunter, by the term fare perinaeum, and that from the coccyx to the anus the hind or back perinaeum.
The cavity of the belly, formed by the above-named parts, all which are covered with the membrana adiposa tad the skin, is lined on the inside by the peritonaeum. This cavity contains the stomach, intestines, mesentery, mesocolon, liver, gall-bladder, spleen, pancreas, glands of the mesentery, vasa lactea, receptaculum Chy-li, kidneys, renal glands, ureters, bladder, and the internal parts of generation.
Though we have employed common language, in the expression of the cavity of the belly, in reality there is no cavity. The peritonaeum may be compared to a flaccid bladder, behind and on the outside of which the intestines and other supposed contents are placed. This membrane is then folded around them, and the two sides of the bladder, after enfolding the intestines, are brought together, forming the mesentery: within these folds of the mesentery the lacteals pass towards the blood vessels. The peritonaeum is therefore contiguous on its internal surfaces, or only separated by a vapour called an halitus, which, after death, condenses into a watery fluid; this fluid in dropsies is greatly augmented, and is said by the more correct authors to be contained in the cavity of the perito-ncnim.
The principal arteries of the belly are, the epigastric, which are the lowest portion of the internal mammary artery, the inferior aorta, the caeliac, the upper mesenteric, the hemorrhoidal artery, the renal, called emul-gent, the spermatic artery, the lower mesenteric artery, the lumbar, the iliac, the lower epigastric arteries, and the pudicae.
The principal nerves of the belly are, the stomachic, formed by the extremity of the eighth pair; the lower portion of the great sympathetic nerves, the two semilunar or plexiform ganglions, the hepatic, splenic, renal, upper and lower mesenteric plexus, the nerves of the loins and sacrum, also the origin of the crural and sciatic nerves.
The appendix ensiformis, the lower pointed extremity of the sternum, the cartilaginous portions of the last pair of true ribs, those of the first four pairs of false ribs, all the fifth pair, the five lumbar vertebrae, the ossa innominata, the os sacrum, the os coccygis, form the bony sides of the cavity of the belly.
The diaphragm, the muscles called, particularly, musculi abdominis, the quadrati lumborum, the psoae, the iliaci, the muscles of the coccyx, and of the intesti-num rectum, form the greatest part of the circumference of this cavity. As auxiliary parts, some portions of the sacro lumbares, longissimi dorsi, etc. might be added.
The muscles belonging to the belly are five pair; viz. the obliqui externi, the obliqui interni, the trans-versales, the recti, and the pyramidales. Their action is necessary to expiration, as they pull down the thorax, and they are very useful in efforts to speak loud: they assist also in the expulsion of the faeces and urine. Some people, who find a difficulty in going to stool, or have a suppression of urine, are said to relieve themselves by pressing the abdomen with their hand: the expulsion of the foetus also is greatly assisted by the abdominal muscles. Mr. Pott was of this opinion. He said, that he had seen a child, which lived nearly three weeks, though it had no abdominal muscles; that this child could not either propel or expel the faeces nor urine perfectly, without artificial aid. Mr. Haighton also found that the most violent stimuli, when applied to the stomach either externally or internally, were in his experiments insufficient to produce an evacuation of its contents, without the concurring efforts of the diaphragm, and muscles of the abdomen.
There is a sinus on each side of the cartilago xiphoi-des, between the transversalis and recti muscles, into which, on the left side, the stomach is sometimes pushed by violent vomiting; a disease called Gastrocele.. This tumor is in the upper part of the linea alba. The disorder is attended with excessive pain, which is greater when the person is up, and gradually goes off when he lies in a horizontal posture, a circumstance which distinguishes the disease. There is a continual vomiting; every thing taken in is immediately rejected; and hence succeeds an atrophy. All hernias of the linea alba require the same management; but this of the stomach demands particular attention. They are easily reduced, and should be kept up by a truss: if the rupture does not recede, the stricture must be enlarged and reduced in the same manner as in other ruptures. Happily this case is very rare; when it occurs, little more can be done than to alleviate general symptoms: if it cannot be returned by the hand, any operation will be a doubtful aid, as inflammation soon comes on, and the admission of air into the cavity of the abdomen immediately increases it.
Pain and other disorders of the belly sometimes happen from keeping it too cool. The circulation of the blood from the viscera in the belly, by the vena portae to the liver, and afterwards in the liver, is greatly promoted by the alternate compression, which the contents of the belly receive from its muscles and the diaphragm: and it is of service in dissecting living animals, that, when the viscera of the belly are exposed to the air, this circulation of the blood towards the liver, by the portae, is much impeded, or totally stopped. Hence it follows, that in proportion as the action of the muscles of the belly is impaired, and the cavity laid open, this circulation, so necessary to the animal economy, must be obstructed.
The muscles of the belly and peritonaeum are subject to inflammations, which have been mistaken for inflammation in the liver or the intestines: to distinguish them, see Hepatitis; Inflammatio musculorum abdominis, et Peritonitis.
The rheumatism sometimes affects the muscles of the belly, which has been mistaken for a colic, or for an inflammation of some of the viscera within: in this case, however, the usual symptoms of inflamed viscera are absent, and the medicines which are useful in the colic are without effect in this complaint.
For the management of wounds in the belly, see the article Vulnus.