The Intestines. 231 



inch above this point. It is hard from an anatomical 

 standpoint to explain the reference of the pain to this situ- 

 ation. The inferior mesenteric plexus for the supply of 

 the lower portion of the large intestine arises about this 

 point, i.e., one inch above the umbilicus, but this plexus 

 does not supply the small intestine, and it is in affections of 

 the small intestine, especially, that the pain is referred to 

 the umbilicus. It may be due to reflex irritation of this 

 plexus, but more likely to implication of the nerves to the 

 great omentum, which is attached to the colon in this situ- 

 ation. These latter nerves arise from the gastro-epiploica 

 sinistra plexus, an extension from the splenic which itself 

 is derived from the solar plexus. 



Syncope, etc. In injuries to the intestine impres- 

 sions are carried by the sensory nerves to the cerebrum, 

 and an efferent impulse may be sent out to the heart 

 through the inhibitory fibres of the pneumogastric, so that 

 syncope results, and in this condition of syncope there is, 

 in all probability, in addition to the reflex inhibition of the 

 heart, a co-existent reflex dilatation of the abdominal 

 bloodvessels through the impression on the sympathetic, 

 In shock there is a more profound impression made on 

 the centres than there is in syncope, so that a marked de- 

 pression of cerebral activity results. Mansell Moulin 

 says, "shock ... is a reflex paralysis affecting all the 

 functions of the nervous system." 



In collapse there is, in addition to dilatation of the ab- 

 dominal vessels, an increased density of the blood, thus 

 reflexly affecting the heart through the medium of in- 

 creased blood pressure (Cobbet). 



In appendicitis the pain may be referred to the um- 

 bilicus, as above mentioned, or it may be reflected to the 

 front of the thigh through the anterior crural which lies be- 

 tween the iliacus and the psoas muscles, and, in all prob- 



