492 



NERVES OF ALIMENTARY CANAL. [BOOK n. 



only means by which the presence of food brings about the move- 

 ments in question, is shewn by the fact that these continue to be 



R.V 



Oe 



Ret 



n.e 



FIG. 70. 



DIAGRAM TO ILLUSTRATE THE NERVES OF THE ALIMENTARY 

 CANAL IN THE CAT. 



The figure is for the sake of simplicity made as diagrammatic as possible, and does 

 not represent the anatomical relations. 



In the cat the thoracic vertebra and nerves are thirteen in number instead of 

 twelve as in man, and the lumbar are seven instead of five. This should be 

 borne in mind in applying the teachings of the diagram to the case of man. 



Oe to Ect. The alimentary canal, oesophagus, stomach, small intestine, large 

 intestine, rectum. 



LV. Left vagus nerve, ending on front of stomach. r.L recurrent laryngeal nerve 

 supplying upper part of oesophagus. R.V. right vagus, joining the left vagus in 

 the oesophageal plexus, Oe. pi., supplying the posterior part of stomach and 

 continued as E'.V. to join the solar plexus, Sol. pi., here represented by a 

 single ganglion. 



Sy., the sympathetic chain joined by the rami communicantes, r.c., from the 

 thoracic nerves VI to XIII, and from the lumbar nerves I to V. The individual 

 ganglia are not shewn, the whole chain being simply represented by a thick black 

 line, for the reason that the ramus communicans coming from a nerve does not 

 always end in the corresponding ganglion, and it would be difficult to shew 

 this, if the several ganglia were introduced. 



With the sympathetic chain, the solar plexus is connected by the great splanchnic 

 Spl. and the lesser splanchnic Spl.mi. 



G.m.i., inferior mesenteric ganglion, or plexus, connected with the lower part of the 

 sympathetic chain, and also joined to the solar plexus by the nerve x. 



The rami communicantes of the thoracic nerves VI to XIII, and of the lumbar 

 nerves I and II, are connected through the sympathetic chain and thus, the 



