ANATOMY OF THE DRILL. 



449 



There is only one splanchnic nerve on the right side, but four 

 form a loop on the left. The connections which they establish 

 through the solar plexus, and by direct branches to the organs, are 

 numerous and complicated, but careful dissection enables one to 

 see the following offshoots : — 



a. Superior mesenteric plexus (S.M.P). 



b. Splenic plexus (S.P). 



c. Left renal and suprai'enal plexuses (L.R.P). 



d. Right renal plexus (R.R.P). 



e. Aortic plexus (A.P). 



f. Inferior mesenteric plexus (I.M.P). 



Text-ficure 22. 



The thoracic and abdominal sympatlietic. L.S. and R.S : left and right 

 sympathetic cords ; L.V : left vagus. Other letters in text. 



The Inferior Mesenteric Plexus sends branches to the lai'ge 

 intestine, and a strong cord i-uns down into the pelvis. Gaining 

 the dorsal aspect of the vesiculse seminales it forms a crescentic 

 expansion, whence branches run to the left sacral plexus and 

 pelvic viscera. 



The Brachial Plexus (text-fig. 23) is formed by the fourth to 

 eighth cervical nerves, and branches of communication run to the 

 cervical plexus and first dorsal nerve (O.C.P and O.D.I). In 

 Macacus rhesus and Homo the fourth nerve only communicates, 



