Page:Encyclopædia Britannica, first edition - Volume I, A-B.pdf/303

 257 Part VI. ANA T O M Y. The eprgaftric region begins immediately under the The appendix enfiformis of the fternum, the cartilagiappendix enliformis, at a fmall fuperficial depreffion, call- nous portions of the laft pair of true ribs, thofe of the ed the pit of the ftomach, and ends abore the navel firft four pairs of falfe ribs, all the fifth pair, the five at a tranfverfe line, fuppofed to be drawn between the lumbar vertebrse, the offa innominata, the os facmm, and os coecygis, form the bony lides of the cavity of the laft falfe ribs on each fide. This region is fubdivided into three parts ; one middle, abdomen. named epigaftrium ; and two lateral, termed hypochon- 7'he diaphragm, the mufcles called particularly mufdria. The epigafirium 'takes in all that fpace which lies culi abdominis, the quadrati lumborum, pfoai, iliaci, the between the falle ribs of both fides, and the hypochon- mufcles of the coccyx, and of the inteftinum reftum, form the chief part of the circumference of this cavity. dria are the places covered by the falfe ribs. The umbilical region begins above the navel, at the The cavity of the abdomen is of an irregularly oval tranfverfe line already mentioned, and ends below the figure, but ftill fymmetrical. On the forefide it is uninavel at another tranfverfe line, fuppofed to be drawn formly arched or oval, and its greateft capacity is even parallel to the former, between the two crilhs of the with the navel, and neareft part of the hypogaftrium. On the upper fide it is bounded by a portion of a’vault, os ilium. This region is likewife divided into three parts ; one very much inclined. On the backfide, it is in a manner middle, which is properly the regio umbilicalis ; and two divided into two cavities by the jutting out of the verlateral, called ilia, or the flanks; and they comprehend tebrae of the loins. On the lower fide, it contradts grathe fpace between the falfe tibs and upper part of the os dually all the way to the little edge of the pelvis, ilium on each fide. and from thence expands again a little as far as the 03 7'he hypogaftric region is extended downward from coccygis and tubercles of the ifehium, terminating in the the inferior limit of the umbilical region, and is divided void Ipace between thefe three parts. into three parts ; one middle, called pubis ; and two lateral, called inguina, or the groins. PERITONAEUM. The lumbar region is the pofterior part of the abdomen, and comprehends all that fpace which reaches from the lowed ribs on each fide, and the laft vertebra Having carefully removed the mufcles of the abdoof the back, to the os faerum and neighbourings parts men, the' firft thing we difeover is the peritonaeum, a of the ofla ilium. The lateral parts of this region are membranous covering, which adheres immediately to the furface of the mufculi tranfverfi, and of all the 0termed the loins, but the middle part has no proper name inner ther parts of this cavity; and involves and inverts all in men. Laftly, the bottom of the abdomen, which anfwers to the vifeera contained therein, as in a kind of bag. the pelvis of the Ikeleton, is terminated anteriorly by The peritonaeum in general is a membrane of a pretty' the pudenda or parts of generation, and polteriorly by dole texture, and yet very limber, and capable of a very, the clunes and anus. The buttocks are feparated by a great extenfion; after which it caq recover itfelf, and be fofla, which leads to the anus; and each buttock is ter- contracted to its ordinary fize ; as we fee in pregnancy,, minated downward by a large fold, which diftinguilhes dropfies, corpulency, and repletion. It feems to be made up at leaft of two portions, one it from the reft of the thigh. The fpace between the anus and the parts of genera- internal, the other external; which have been looked tion, is called perinaeum, and is divided into two equal upon by many anatomifts as a duplicatnre of two diflateral parts by a very diftinft line, which is longer in tirtdt membranous laminae. But, properlyIpeaking, the internal portion alone deferves the name of a memmales than in females. The cavity of the abdomen, formed by the parts al- branous lamina, as being the main body cf the peritoready mentioned, (all which are covered by the fldn naeum. The external portion is no more than a kind and membrana adipofa) is lined on the infide by a parti- of fibrous or follicular apophyfis of the internal; and cular membrane, called peritonasum. It is feparated may properly enough be termed the cellular fubftance of from the cavity of the thorax by the diaphragm, and ter- the peritonaeum. The true membranous lamina, commonly called the; minated below by the mufculi levatores ani. This cavity contains the ftomach, and the inteftines. internal lamina, is veryfmooth, and poliftied on that fide It contains likewife the mefentery, mefocolon/omentum, which is turned to the cavity and vifeera of the abdomen, liver, gall bladder, fpleen, pancreas, glands of the me- and continually mbiftened by a ferous fluid difeharged fentery, vafa la<5iea, receptaculum chyli, kidneys, renal through almoft imperceptible pores. glands, ureters, bladder, and the internal parts of ge- The cellular fubftance, or external portion of the peritonaeum, adheres very clofely to the parts which form neration in both fexes. The whole fore-part of the abdomen forms an oblong the infides of the cavity of the abdomen. convexity, like an oval vault, more or lefs prominent in The cellular fubftance has feveral elongations, which the natural ftate, in proportion to the quantity of fat up- have been called productions of the peritonaeum. Two on it, and of food contained in it, or to the different of thefe productions accompany and invert the fpermatic degrees of pregnancy in women. The hypogaftric and ropes in males, and the vafcular ropes, commonly called -umbilical regions are moreTubjoiffto thefe varieties, than the round ligaments, in women. 7'he re are other two, tbe epigaftrie region. which pafs under the liganientum Faiioppii, with .the Vol. I. Numb. 11. 3 7’ cmral 3