976 HUMAN ANATOMY. 



The nodes which are associated with the abdominal portions of the large intestine 

 are known as the mesocolic nodes ( lymphoglandulae mesocolicae) and they consist 

 of from twenty to fifty small nodes which are situated close to the intestine (Fig. 8i8). 

 Their afferents are received from the entire length of the large intestine, with the 

 exception of the caecum and appendix and the rectum, and the effej-ents of the nodes 

 associated with the ascending colon and the right half 6f the transverse colon pass to 

 the lower coeliac nodes, while those of the nodes associated with the left half of the 

 transverse colon and with the descending and sigmoid colons pass to the median row 

 of lumbar nodes. 



In addition to the nodes which are properly included in the mesocolic group 

 there are a number of small nodes situated upon the lateral walls of the upper part of 

 the rectum, along the lines of the superior hemorrhoidal vessels (Fig. 821). These 

 ano-rectal nodes are from two to eight in number on each side, and are situated 

 beneath the fibrous investment of the rectum, resting directly upon the outer surface 

 of the muscular coat. They receive their afferents from the neighboring portions of 

 the wall of the rectum and, in the female, from the posterior surface of the \agina, 

 and their efferents pass to the mesocolic nodes situated in the lower part of the 

 mesentery of the sigmoid colon. 



The Lymphatic Vessels. 



The Abdominal W^alls. — The anterior abdominal wall, as regards its 

 lymphatic vessels, may be divided into a supra- and an infra-umbilical region. The 

 lymphatics of the former area belong in reality to the thoracic cutaneous set, passing 

 upward to join the thoracic stems which terminate in the anterior pectoral nodes of 

 the axillary plexus. The vessels of the infra-umbilical region, on the contrary, 

 descend to terminate in the inguinal nodes. Along the line of junction of the two 

 regions anastomoses occur and the \-essels of the right half of the abdominal wall also 

 communicate with those of the left half. The subcutaneous vessels of the posterior 

 abdominal and lumbar regions anastomose with the corresponding \'essels of the 

 posterior thoracic region above, and below with those of the gluteal region. They 

 form an extensive net-work, from which stems pass downward and forward, parallel 

 with the crest of the ilium, to terminate in the inguinal nodes. 



The lymphatic net-work of the deeper structures of the abdominal walls is 

 drained by a number of stems which follow in general the courses of the blood- 

 vessels. Thus, the stems which lead away from the upper portion of the abdominal 

 wall pass upward along the course of the superior epigastric vessels to terminate in 

 the lower sternal nodes ; another set follows the course of the deep epigastric vessels 

 to terminate in the lower iliac nodes, after traversing the epigastric nodes ; another 

 accompanies the deep circumflex iliac vessels, draining the lower portions of the lateral 

 walls of the abdomen, traversing the circumflex iliac nodes, and also terminating in 

 the iliac nodes ; while other sets accompany the lumbar xessels and terminate in the 

 lateral rows of lumbar nodes. Abundant communications exist between the vessels of 

 adjacent drainage areas and from the region of the umbilicus the lymph flow may follow 

 any one of the paths mentioned above. Attention may be called to the occasional 

 presence of nodes in the course of the vessels arising in the umbilical region (page 972). 



The Stomach. — The lymphatics of the stomach have their origin in two 

 net-works, one of which is situated in the mucosa and the other in the muscular 

 coat. The net-work of the mucosa occurs uninterruptedly throughout the entire 

 extent of the gastric surface and is continuous with the corresponding net-works of 

 both the oesophagus and duodenum. From its deeper surface branches pass to a 

 more open net-work situated upon the outer surface of the submucosa, and from this 

 stems traverse the muscular coat obliquely to terminate in a subserous net-work which 

 also receives branches from the net-work of the muscular coat. Connections between 

 the muscular and mucous net-works occur, but they are so indirect that an extensive 

 cancerous infection of the mucosa may reach the outer layers of the stomach only at 

 limited areas at some distance from one another. 



The subserous net-work with which both primary net-works communicate gives 

 origin to a number of stems which pass to the gastric nodes, and the course which thev 

 follow is such that the entire surface of the stomach may be regarded as presenting 



