THE SYMPATHETIC NERVE. 139 



What are the other Ganglia of the Sympathetic ? There are 

 on each side of the vertebral column II or 12 dorsal ganglia, 4 or 5 

 lumbar, 5 sacral, besides the single coccygeal Ganglion Impar in which 

 terminates the double chain. Connected with the viscera are many ganglia, 

 from which branches ramify around the arteries in plexuses named from 

 their locations. 



Describe the Splanchnic Nerves. They are 3 in number on each side, 

 and are derived from branches of the 6 lower thoracic ganglia, as follows, 

 riz. 



Great Splanchnic, from branches of the 6th to the loth, connecting with the 

 upper six, passes through the posterior mediastinum, perforates the crus 

 of the diaphragm, to the semilunar ganglion. 

 Lesser Splanchnic, from the loth and nth, passes through the diaphragm 



with the great splanchnic, to the cceliac plexus. 



Smaller or Renal Splanchnic, from the last thoracic ganglion, also perforates 

 the diaphragm, and ends in the renal and coeliac plexuses. 



Describe the Solar Plexus. This plexus, called also the " abdominal 

 brain," is a network of nerves and ganglia, chiefly formed by the splanchnic 

 nerves and the right pneumogastric. It lies behind the stomach, and in front 

 of the aorta and the crura of the diaphragm, surrounding the cceliac axis and 

 the root of the superior mesenteric artery. Its two largest ganglia are the 

 Semilunar Ganglia situated in front of the crura of the diaphragm. From it 

 are derived branches which form Plexuses over most of the abdominal arteries, 

 as follows : 



Phrenic. Gastric. Splenic. Renal. Superior Mesenteric. 



Cceliac. Hepatic. Suprarenal. Spermatic. Inferior Mesenteric. 



Describe the Carotid and Cavernous Plexuses. They are two plexuses 

 of the sympathetic, situated on the internal carotid artery, the Carotid lying on 

 the outer side of the artery, as it lies by the side of the body of the sphenoid 

 bone ; and the Cavernous being on the inner side of the artery, below its last 

 bend, in the upper portion of the cavernous sinus. The 



Carotid Plexus, is connected by numerous filaments with the 6th nerve 

 ' and the Gasserian ganglion, and furnishes the Large Deep Petrosal to 

 unite with the large superficial petrosal of the facial, to form the Vidian 

 nerve ; also the Small Deep Petrosal, to join the tympanic plexus prob- 

 ably. 



Cavernous Plexus, communicates with the 3d and 4th nerves and the 

 ophthalmic division of the 5th, and gives a branch to the Ciliary ganglion 

 in the orbit. 



