INTESTINES. 



« -large and loofe fold, rerembling in its form the letter S ; 

 paflcs over the left facro-iliac fyniphyfis into the pelvis, runs 

 alon J the concave furface of the facrum and os coccj-gis, and 

 ends a httle beyond the anterior extremity of that bone, at 

 the anus. 



We may diftincruifh fix portions of the large inteftine : 



1, the cacjf, which is cominonly named Cmply the caecum : 



2, the vermiform, ordinarily called procefTiis or appendix 

 vermiformis cn?ci : 3, tlie r/'ffo part of the colon, or tlie 

 afcending portion : 4, the tranf-ucrfe part, or the arch : 

 5, the left part, including the dcfcending colon and the iig- 

 moid or iliac flexure of the gut : 6, the rcchim. Very com- 

 monly the tube is divided into the three parts, cxcum, colon, 

 and rcftum. Tliefe different names, as in the fniallintelUne, 

 have led to the employment of the phrafe large inlt/lines in 

 the plural, as if there were more than one tube. 



We cannot adign any exaft limits to thefe divifions, as 

 the polition of the inteftine, on which they are founded, 

 varies in its different ftatcs of diftcntion or emptinefs. The 

 right colon defcends lower, and appears longer wlien it is 

 full than when empty. The tianfverfe portion, wlien filled, 

 may defcend, from tlie loofenefs of its attachmei^, to the 

 umbilicus or pelvis : if it be longer than ufual, it forms an 

 arch with the concavity upwards, or it may make one or 

 two turns. When removed from the body, all diilindion of 

 particular divilions is loft, and the gut forms a llraight unin- 

 terrupted tube. It is from three to five times (horter 

 than the fmall inteftine, and they are to each other nearly as 

 five to twenty-five. In individuals of good proportions it 

 meafures about feven feet. The connefiions of the inteftine 

 are more firm in fome fituations, and more loofe in others. 

 In many parts the peritoneum does not entirely furround the 

 tube, but covers its anterior portion only, leaving the pof- 

 terior part to be affixed by cellular fubftance to the conti- 

 guous organs. The term mefocolon is applied generally to 

 the peritoneum covering the large inteftine. 



The mefocolon dextrum paffes from the under and back 

 part of the liver, from the apex of the laft rib, from the 

 right quadratus lumborum, and iliacus internus, in front of 

 the right colon and coecum. Thus thefe parts, which are 

 only covered on their anterior furface, are firmly bound to 

 the ihac mufcle, the kidney, liver, and duodenum, and con- 

 ftantly held in this fituation. The appendix has itspecuhar 

 fmall and falciform mefentery. 



The tranfverfe mefocolon is a broad and loofe fold, by 

 ■which the tranfverfe part of the inteftine is uniformly covered, 

 except jull at the feparation of its two lamina. The left 

 raefocoJon is infiefted towards the right, nearly at a right 

 angle, and is then continued behind and below the itomach 

 and hver, in a tranfverfe direction to the left kidney, under the 

 name of mefocolon tranfverfum. Together with the arch of 

 the colon, it forms a kind of tranfverfe partition or dia- 

 phragm, loofe at the anterior edge, and feparating the fto. 

 mach, duodenum, fpleen, and liver from the other abdominal 

 contents. It is generally horizantal, as its name denotes ; 

 hut it is fometirnes fo broad and long as to defcend with the 

 inteftine into the pelvis. It is made up of two lamince of 

 peritoneum, including between them, befides the blood- 

 v«ffels, the abforbents with their glands, and the nerves of 

 the inteftine, conncded and covered by more or lefs fat, the 

 .duodenum, and pancreas. The latter parts are placed quite 

 at tke root of the fold. 



The upper lamina defcends from the fplenic fold of the 

 peritoneum, the pancreas, the upper lumbar vertebrx, the 

 external covering of the duodenum, and the neighbourhood 

 of the kidney and vena cava- The inferior lamina, which 

 it more iimple and ftrong, comes od the left from the fitua- 

 6 



tion under the fpleen, where it furrounds the duodenum hj 

 a kind of femilunar fold ; then from the right kid:iey, 

 and from a fold placed between the liver and kidney. 



The breadth of this mefocolon leaves the arch of the in- 

 teftine quite moveable, fo that its fituation is by no means 

 conftant ; the diftended ftomach pufties it downwards, and 

 the repletion of the fmall inteftine has the contrary effeCl. 

 The great omentum covers the front of the tranfverfe colon, 

 and paffes between this and the ftomach : but does not tend 

 at all to fix it. 



The mefocolon finiftrum is continued over the inteftine, 

 from the iliac veffels and pfoas magnus to the left kidney : 

 covering only the anterior furface. The back of the intef- 

 tine is connecled by cellular fubftance to the diaphragm, the 

 pfoas, and the kidney, fo that its fituation is very fixed. 

 Sometimes, however, there is fometliing like a mefentery 

 belonging to this part of the tube. 



The meforetlum is a dupllcature, varying in breadth, pro- 

 duced from the fide of the pelvis to the figmoid flexure of 

 the colon, and the commencement of the refhum. I: is 

 broadeft above, where it is continuous with the mefocolon 

 finiftrum, and ends in an acute point below. It is niade up, 

 like the mefentery, of two laminx of peritoneum, including 

 between them the blood-veffels, &c. of the inteftine, and fat, 

 and feparating to cover the reftum. It allows the inteftine a 

 conliderable liberty of motion. Below the termination of 

 the meforeftum, the gut has no peritoneal coat ; but is 

 united by cellular fubftance to the furrounding organs : that 

 is, to the facrum and os coccygis, to the vagina in the fe- 

 male, to the bladder and proibte in the male. Its extremity 

 is ftill furtlier fixed by the attachment of the mufcles of the 

 amis, and by its continuity with the common integuments. 

 The diameter of the tube, when moderately diftended, is 

 about two inches or two and a half. 



The ileum defcends gently to the right iliacus internus 

 mufcle, and is inferted obhquely into the left and pofterior 

 fide of the large inteftine, between the cascuni and right 

 colon, having its mufcular and mucous coats continuous with 

 thofe of the large inteftine. This extremity of the fmall in- 

 teftine forms an acute angle with the cscum, and a right an- 

 gle with the colon : its upper half is placed tranfverfely, the 

 lower afcends. On opening the large inteftine, we find the 

 communication to be of a valvular nature, and compofed of 

 two folds (alit or labia), a fuperior and an inferior one : it is 

 prominent, foft, and of courfe moveable. Each of thefe 

 folds is compofed of a fmaller internal lamina, which is the 

 mucous lining of the fmall inteftine, and an external larger 

 one, compofed by the correfponding coat of the large. Thefe 

 laminx, connedled by cellular fubftance, and continuous with 

 each other at the fides of the opening, form the valvula coli 

 (valvula ilii, or ileo-collca, or lleo-caetahs). The fupericr 

 fold, placed nearly tranfverfely, is ftiorter and narrower thai4 

 the Inferior, which riles the higheft of the two. A kind 

 of flrldure or fold of the large inteftine bounds the valve 

 on each fide. Bctv.-een the two folds compofing this 

 valve, the orifice of the fmall inteftine opens tranfverfely ; 

 its figure is an oblong oval, and its dimenfions are much lefs 

 than the diameter of the ileum.. The length and breadth of 

 the folds, and confequently the fize of tlie interpofed aper- 

 ture, vary greatly. Sometimes the lower fold is very long and 

 broad, the upper Ihort and narrow, fo that the inteftine 

 opens obliquely by a very fmall aperture. This ftrufture 

 admits of the opening being very completely clofed. Some- 

 times botli folds are but fllghtly prominent, and their diftiuc- 

 tion not clearly marked. Here the opening is more nearly 

 circular, and cannot be fo perfecily fliut. 



The external or peritoneal coa; puifcs over the communica- 

 tion 



