THE DUODENUM. 501 



duodenum, the transverse meso-colon, the right kidney, and supra- 

 renal capsule ; this surface forms the anterior boundary of that cul 

 de sac of the peritoneum which is situated behind the lesser omen- 

 turn and extends into the 'greater omentum. 



Small Intestines. The small intestine is about twenty-five feet in 

 length, and is divisible into three portions, duodenum, jejunum, and 

 ileum. 



The Duodenum (called SuSexaSaxrvhw by Herophilus) is some- 

 what larger than the rest of the small intestines, and has received 

 its name from being about equal in length to the breadth of twelve 

 fingers. Commencing at the pylorus, it ascends obliquely back- 

 wards to the under surface of the liver : it next descends perpendi- 

 cularly in front of the right kidney, and then passes nearly trans- 

 versely across the third lumbar vertebra; terminating in the 

 jejunum on the left side of the second lumbar vertebra, where it is 

 crossed by the superior mesenteric artery and portal vein. The 

 first or oblique portion of its course, between two and three inches, is 

 completely enclosed by the peritoneum : it is in relation, above with 



* A vertical and longitudinal section of the stomach and duodenum, made in such a 

 direction as to include the two orifices of the stomach. 1. The oesophagus ; upon its 

 internal surface the plicated arrangement of the cuticular epithelium is shown. 2. 

 The cardiac orifice of the stomach, around which the fringed border of the cuticular 

 epithelium is seen. 3. The great end of the stomach. 4. Its lesser or pyloric end. 

 5. The lesser c.urve. 6. The greater curve. 7. The dilatation at the lesser end of 

 the stomach which received from Willis the name of antrum of the pylorus. This 

 may be regarded as the rudiment of a second stomach. 8. The rugce of the stomach 

 formed by the mucous membrane : their longitudinal direction is shown. 9. The 

 pylorus. 10. The oblique portion of the duodenum. 11. The descending portion. 12. 

 The pancreatic duct, and the ductus communis choledochus close to their termina- 

 tion. 13. The papilla upon which the ducts open. 14. The transverse portion of the 

 duodenum. 15. The commencement of the jejunum. In the interior of the duodenum 

 and jejunum, the valvulae connivcntes are seen. 



