THE DUODENUM. 565 



The small intestine reaches from the pylorus to the 

 ilio-co3cal valve in the right iliac region. It is about an 

 inch in diameter, is very much convoluted, and occupies 

 principally the umhilical and hypogastric regions. 



The large intestine is much greater in size than the 

 small, though only ahout one fifth of its length, and ex- 

 tends from the right iliac region to the anus, occupying the 

 most of the abdominal regions, and surrounding the small 

 intestine like a ruffle. The whole of the intestinal canal 

 has the same number of coats as the stomach ; serous, mus- 

 cular, cellular and mucous. There are some differences, 

 however, in this canal, which we shall briefly notice under 

 its respective divisions. 



THE DUODENUM. 



The duodenum, so called from being twelve fingers' 

 breadth in length, is the shortest portion of the small in- 

 testine, though it has the greatest capacity. It is situated 

 P IG> IQI in the right hypochondriac, right 



lumbar, and portion of the um- 

 bilical regions. It takes a semi- 

 circular course. Commencing at 

 the pylorus, it ascends to the 

 under surface of the liver, then 

 makes a turn called its superior 

 angle, and descends vertically in 

 front of the right kidney as low 

 as the third lumbar vertebra, where it makes a second turn, 

 the inferior angle, then passes to the left side of the second 

 lumbar vertebra, crossing the spine, and beneath the su- 

 perior mesenteric artery, terminates in the jejunum. In 

 consequence of its great dilatation, it has by some been 

 regarded as a second stomach. 



The peritoneal coat of the duodenum furnishes a complete 



FIG. 181 represents the Interior of Duodenum and a portion of the Stomach. 

 a a Pyloric end of stomach. 6 6 Folds and follicles of the mucous coat of the 

 stomach, c Looks into the pylorus, d Thickness of pylorus, e e Rugae of mucous 

 coat of duodenum. / Point of entrance of the ductus communis choledochus. 



