320 ANATOMY IN A NUTSHELL. 



LESSON XCI. 



The first part of the small intestine is called the duodenum; the literal 

 meaning of which is twelve finger lengths, hut this is not twelve finger lengths or 

 twelve finger breadths. It has a mesentery. The duodenum may consist of 

 five portions, the transverse, descending, inferior transverse, ascending, and 

 the flexure — duodeno-jejunal flexure. It has glands in it called Brunner's 

 glands or duodenal glands. 



The next part of the small intestine is called jejunum, and the third part is 

 called ileum. The first portion consists of about three-fifths of it below the 

 duodenum, and the ileum about two-fifths. The glands in the ileum are called 

 Peyer's pan lies winch are about thirty in number; the intestine is thinner here 

 than in other parts. The small intestine straightened out would be in the shape 

 of a slender cone, with the base corresponding to the stomach end, and its apex 

 corresponding to the point where it joins the caecum. 



The large intestine consists of first, the cecum which may be various shapes 

 and is partly covered with peritoneum; the next part is the ASCENDING COLON 

 which in 27 per cent of casts is covered with peritoneum; it is about eight and 

 one-half inches long. The next portion is the hepatic flexure which joins 

 the ascending with the transverse colon. This transverse colon is about 

 twenty inches long, and is covered with peritoneum. The next part is the 

 splenic flexure which joins the transverse with the descending colon. The 

 descending colon is about nine inch's in length and in 37 per cent of cases is 

 covered with peritoneum. The next part is called the sigmoid flexure, which 

 is about fourteen inches in length. The last part is the rectum (which means 

 straight): it is not straight but relatively straight compared with the rest of 

 the alimentary canal. 



The glands of the large intestine are less numerous, and lie along the 

 vascular arches of the arteries or even upon the gut itself; they are fewest along 

 the transverse colon. 



The lymphatic vessels of the large intestine form two sets, viz., those of the 

 caecum, ascending and transverse colon, which pass through their proper glands 

 to the mesenteric glands; and those of the descending colon, sigmoid flexure, 

 and rectum which pass to the lumbar glands. 



The small intestine (intestinum tenue,) (Plate CL VI) , extends between the 

 stomach above and the large intestine below. Its average length is about 

 twenty-two fe< t. It may be as many as thirty-four feet or as few as eight feet 

 in length. [ts diameter diminishes in size from about two inches above to less 

 than oik inch below. It is to a huge extent within the area bounded by the 

 colon, occupying the umbilical and hypogastric regions and the adjacent por- 

 tions of the lumbar. It has four coats which correspond in general arrange- 

 ment and character to those of the stomach. They are the serous, muscular, 

 areolar, and mucous. The divisions of the small intestine are the duodenum 

 (twelve finger intestine,) jejunum (empty intestine.) and ileum (curved or 

 twisted intestine.) The villi are small projections on the mucous membrane of 



