ABDOMINAL CAVITY 511 



fibres may be seen by the naked eye when a longitudinal 

 section is made through the pyloric canal in the plane of the 

 two curvatures of the stomach (Fig. 196). 



Coats of the Duodenum. In connection with the duo- 

 denum, note that the plicae circulares begin one or two inches 

 beyond the pylorus, about the commencement of its second 

 part ; that the mucous membrane is covered by villi ; and 

 that no solitary lymph nodules are to be seen. 



A segment of the wall of the first part of the duodenum should now be 

 pinned down, with its mucous surface undermost, to the bottom of a cork- 

 lined tray filled with water. Its coats may then be dissected. They are in 

 all respects similar to those already examined in connection with the 

 jejunum (p. 485). If the dissection is carried on until the deep surface of the 

 submucous coat is exposed by the removal of the entire muscular coat, a 

 view of Brunner's glands may be obtained. They appear as whitish specks, 

 about the size of hemp-seed, in the submucous tissue. They are most 

 numerous close to the pylorus, and gradually disappear about two inches 

 beyond this. 



Lien (Spleen). The spleen is a solid organ, which lies deeply 

 in the left part of the costal zone, and is altogether out of 

 sight in the undisturbed condition of the viscera, but it is 

 exposed when the stomach is removed. It lies very obliquely 

 in the abdominal cavity, its upper end being much nearer the 

 medial plane and much further back than its lower end. 

 Its long axis is directed from above downwards and laterally, 

 and also to some extent forwards. For the most part it lies 

 in the left hypochondrium, but its upper end extends 

 medially beyond the left lateral plane, so that fully a third 

 of the organ is situated in the epigastric region. 



The spleen when properly hardened in situ has the shape 

 of an irregular tetrahedron. The upper extremity is curved 

 to some extent forwards on itself, and approaches close to 

 the left suprarenal gland. 



Of the four surfaces the most extensive is the fades 

 diaphragmatic^ which is convex and looks backwards and 

 laterally. It rests upon the posterior part of the diaphragm, 

 to the curvature of which it is adapted, and it is separated 

 by the diaphragm from the ninth, tenth, and eleventh ribs. 

 It is necessary also to remember that the pleura descends 

 between this portion of the chest wall and the diaphragm, 

 and comes to lie superficially to the greater part of the 

 diaphragmatic surface of the spleen. The thin basal margin 

 of the lung, which occupies the upper part of the pleural 



