298 THE ABDOMEN AND PELVIS 



The Veins of the Stomach correspond to the arteries and 

 terminate in the portal vein, or in the two large vessels which 

 form it, viz. the superior mesenteric and the splenic. At the 

 cardia, the coronary vein anastomoses freely with the cesophageal 

 veins through the cesophageal opening in the diaphragm. In 

 this situation, therefore, an important communication occurs 

 between the portal and systemic circulations, and the veins at 

 the inferior end of the oesophagus consequently become enlarged 

 and varicose in portal obstruction. Their rupture gives rise to 

 haematemesis which may be the first sign of the condition. 



The Nerve-supply of the Stomach is derived from both 

 vagi, and from sympathetic fibres which are associated with 

 the arteries and derived from the cceliac plexus. The sympathetic 

 nerves leave the spinal medulla in the mid-thoracic region 

 (T. 5-8). Referred pain frequently occurs in connection with 

 gastric disorders, and its site is most commonly the epigastrium. 

 The afferent impulses from the viscus are such that a " focus of 

 irritation " (Mackenzie) may be established in the mid-thoracic 

 region of the spinal medulla. As a result stimulation of the 

 terminal fibres of the afferent nerves which are connected with 

 the segment or segments involved produces an abnormal 

 response. In this way, localised hyperaesthetic or hyperalgesic 

 areas of skin and muscle may be explained. As the proximal 

 part of the stomach is supplied by the nerves which arise from 

 the higher segments of the spinal medulla, the situation of 

 these areas on the surface of the body should give an indication 

 of the site of the gastric lesion. Thus a hyperaesthetic area due 

 to an ulcer near the cardia should be in the upper part of the 

 epigastric region (T. 6, Fig. 72), whereas a similar area due to 

 a lesion near the pylorus should be in the lower part of the same 

 region (T. 8). 



In the examination of patients suffering from gastric disorders, 

 the areas supplied by the posterior rami of the 5th-8th Th. 

 nerves should also be tested, as hyperaesthesia and hyperalgesia 

 of the skin of the back and the underlying sacro-spinalis muscle 

 are frequently present. 



Examples of the viscero-motor reflex (p. 251) are also 

 commonly found in gastric mischief. They give rise to localised 

 areas of contraction in the upper parts of both recti (more 

 especially the left) and also in the sacro-spinalis. 



The Lymph Vessels of the Stomach anastomose freely 

 with one another in its walls, but the lymph flow passes in 



