THE LYMPHATICS OF THE ABDOMEN. 



979 



Ano-rectal 

 codes 



The mesocolic nodes associated with the descending colon are less numerous 

 and smaller than those of the sigmoid flexure and resemble in appearance and 

 arrangement those of the ascending colon. 



The lymphatics of the rectum (Fig. 821) although belonging in large part to the 

 pelvic region, may, for the sake of completeness of the account of the intestinal 

 lymphatics, be considered here in their entirety. Of the two primary net-works that 

 of the muscular coat is injected only with difSculty, but it communicates with the 

 mucosa net-work and its collecting stems follow the same course as those of the 

 deeper net-work. In the mucosa net- work two zones may be distinguished, one of 

 which includes the greater portion of the net-work and extends down to the lower 

 ends of the columns of Morgagni, while the other includes that portion of the mucosa 

 intervening between that level and the anal integument. The upper zone may be 

 termed the net-work of the rectal mucosa, while the lower one may be designated 

 as the net-work of the anal 



mucosa, since the region in Fig. 821. 



which it occurs forms the 



transition between the mu- T- ^ 



cosa and the anal integument. 



The collecting stems 

 from the net-work of the 

 rectal mucosa traverse the 

 muscular coat and enter into 

 relation with the ano-rectal 

 nodes ( page 976 ). After 

 traversing these they are 

 continued onward along the 

 course of the superior hemor- 

 rhoidal vessels and open into 

 the lower mesocolic nodes, 

 from which ef^erents pass to 

 the median lumbar nodes 

 situated in the neighborliood 

 of the origin of the inferior 

 mesenteric artery. The net- 

 work of the anal mucosa sends 

 numerous branches upward to 

 communicate with the lower 

 part of the rectal mucosa net- 

 work. These branches trav- 

 erse for the most part the Lymphatics of rectum. {Gerota.*) 



columns of Morgagni in which 

 they are so numerous as to earn for themselves the appellation of glomi lyrnphatia, 

 while, on the other hand, the mucosa of the depressions between the columns is 

 comparatively poor in lymphatics. Some collecting stems from the anal mucosa 

 perforate the muscular coat and pass to the ano-rectal nodes, and thence along with 

 the stems from the rectal mucosa to the lower mesocolic nodes, while others follow 

 the course of the middle hemorrhoidal vessels and terminate in nodes belonging to 

 the hypogastric group (page 984) situated at the point where the internal iliac 

 artery divides into its leash of branches, or else at the level of the great sacro-sciatic 

 notch, a little below the point where the obturator vein joins the internal iliac 



The lymphatics of the anal iniegiwie7it will be considered together with ttiose of 

 the perineal region (page 987). 



The Pancreas. — The lymphatics of the pancreas take their origin from a 

 perilobular net-work from which collecting stems pass to the neighboring nodes, 

 following the course of the blood-vessels which supply the gland. The great majority 

 of them pass to the chain of splenic nodes which extends along the upper border of 

 the pancreas, but those of the head of the gland pass in part to nodes of the hepatic 



Net-work 



ID anal 



mucous' 



membrane 



Lyn^phalics of rectum. 



Net-work in anal 



integument 



*Archivf. Anat. u. Physiol., 1895. 



