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ANA T O M Y. 2^1 Part VI. mon fold of the caecum and colon, it forms two produfiions, which M. Morgagni calls the fraena of the INTESTINUM COLON. coli. The colon is the moft confiderable of all the inteftines. valvula The membranous-coat pf the extremity of the ileum, From the csecum, of which it is a continuation, it is continued and colon, without finking reaches, in form of an arch, above the umbilical region, into any fold,onat thethecsecum place where the ileum enters the and to the lower part of the left hypochondrium. Its colon. continuity is however a little interrupted by the ileum, This valvulacoli is contrived to hinder the return of the which advances into the cavity of the colon, and, together excrements into the ileum; it produces this e!Fe£l: partwith- a certain fold of that inteftine, forms what is called ly as a valve, and partly as a kind of fphinfter. valvula coli. arch of the colon is contraifted by both The whole convex fide of the colon is divided longi- The capacious to the regio lumbaris, near the kidneys, by tudinally into three patts, by three ligamentary bands, extremities two particular ligaments, on the right fide, the other continued from thofe of the caecum, and of the fame on the left, which are onlyonefmall ftructure with thefe. Two of the three bands run on tonaeum, more or lefs tranfverfe. duplicatures of the perieach fide, along the great curvature of the colon; and The remaining portion, which forms the two conthe third along the ima'll curvature. in form of the roman S, contradts below the Thefe three longitudinal bands do the office of fraena, volutions left kidney, being narrower there, than lower down. between which this inteftine is through its whole length The coats this portion become gradually thicker and alternately depreffed into tranfverfe folds, and raifed in- ftronger,, andof likewife ligamentary bands, which ap.to confiderable eminences.. All the folds are duplica- proach each other by the degrees, and feem to increafe in tures, which form portions of valvulae conniventes in the breadth. cavity of the inteftine ; and the eminences form receptacles, called the cells of the colon. The common coat, on one fide, is a continuation of the INTE STINUM RECTUM and ANUS. mefocolon; and, on the other fide, it contributes, by the The laft of all the inteftines, is named reflum, or the {height gut, which, properly fpeaking, is a true contifame continuation, to form the omentum. The arch of the colon begins under the right kidney, nuation of the laft convolution of the colon ; and it is the fink, and common fewer, of the whole intertinear the haunch. It runs up on the fOrefide of that kid- repofitory, ney to which it is connefted, paffes under the vef^cula ll al canal. fellis, which tinges it with a yellow colour at that place, The redtum' haying parted below the laft vertebra of to the infide of the os facrum, is bent backand continues its courfe before the firlt incurvation of the loins, on that concave fide to which it is connefted ; and. the duodenum, to which it adheres, and partly hides it. ward In. this part of its courfe, therefore, there is a remark- having reached the os coccygis, it runs likewife in the able connexion between the colon, duodenum, right direction of that bone, and bends a little forward, terminating beyond the extremity of the cbccyx. kidney, and veficula fellis. From thence the arch of the Colon runs before The figure of this inteftine varies according as it is. the great convexity of the ftomaclv and fometimes a full or empty. When empty, it is irregularly cylindrilittle lower ; then turns backward under the Ipleen, in cal, and finks in by a kind of tranfverfe folds ; and in that the left hypochondrium ; runs down on the forefide of Irate, it is about three fingers‘breadth in diameter, more lefs. When full, it is wider in proportion to the the left kidney, to which it is conne&ed; below this orquantity of fasces, wind, or wlratever elfe is contained kidney turns toward the vertebrae, and terminates th^re by a double incurvation, or by two oppofite convo- in it; and it may be extended to the fize of a large bladder, lutions, which reprefent in feme meafure an inverted ro- fb as to reprefent a kind of ftomach. 7'be membranous coat often contains a great quantity man S. coat, and At the place v/here the caecum joins the colon, one of fat, fpread between it andL the mufcular eminences, in the portion of the circtimference of both is deprefied, and forming round the intertine numerous forms a large fold on the infide, which advances into room of the appendices adipofas of the colon. the cavity of the intelline. It is a little open in the The mufcular or flefhy coat is very thick: the longimiddle, and its extremities are very thick, by reafon of tudinal fibres, which in the. other inteftines are very tlii i, the mutual duplicature of the coats of the caecum and colon. are in this ftrbnger than the circular fibres of the reft. bands continue to iticreafe in breadth, The extremity of the ileum is as it were grafted in Thetoligamentary approach each other. the opening of jhis fold, and ftrongly united to its fides andThe nervous or filamentous and interodl coats, are by the adhefion of its tranfverfe fibres to the tranfverfe larger here, than in the other inreftines; and when, the fibres of the caecum and colon. This union forms a pretty thick ring, which likewife retrtum is empty, they form a great number of waving ruadvances into the common cavity of the caecum and co- gae in its cavity, which difappear, in proportion as that lon, where it is wrinkled or formed into gathers, al- cavity is filled. mofi: like the lower extremity of the cefophagus, the The innermoft coat is very improperly termed villofa, pylorus or infide of the anus. Its circumference is more •and fcarce deferves the name of papillaris, becaufe of 'or lefs oval ; and, by a kind of continuity with the cora- the fmallnefs of .the little corpufdes fpread on its furface. Vol. I. Numb. ii. '3 3U it
