198 



THE NERVOUS SYSTEM. 



The third gang-lion {Ganglion cardiacnm basale, Gaskell andGadow) 

 is sometimes fused with the second, but is usually close to the third 

 spinal nerve : it has a short but distinct Ramus communicans. 



Behind the third gang-lion the sympathetic cord is continued back- 

 wards along the corresponding aortic arch, then parallel with and 

 close to the abdominal aorta (Figs. 117, 127, and 131), receiving 



Rami communicanles, which are 

 long and well marked, from 

 each of the spinal nerves ; 

 the fourth, fifth, and sixth 

 nerves usually supply each 

 one Ramus communicans, the 

 seventh two, and the eighth 

 and ninth each two or three : 

 from the tenth nerve it re- 

 ceives three or more, as many 

 as twelve having been noted. 

 The ganglia are usually more 

 or less spindle-shaped or flat- 

 tened and triangular; the 

 hinder part of the cord usually 

 receives in addition two or 

 three branches from the sciatic 

 plexus and twigs from the 

 R. abdominalis of the N. 

 coccygeus. 



The branches and commu- 

 nications of the sympathetic- 

 cords are as follows : 



a. Communicating branches 

 between the two cords : these 



Sympathetic cord. From Ecker (Icones physiologicae, 



PI. XXIV, Fig. 3). 

 The heart, lungs, and liver have been removed ; the 



stomach, intestine, kidneys, and testes drawn to the 



right side ; the left sympathetic cord is thus pulled 



to the right side to expose the Rami communicantes. 



s Sympathetic cord attached to the ganglion of the are extremely numerous and 



irregular, forming a net-like 



The numbers refer ta the ganglia, which are enumer- 

 ated from before backwards. pleXUS, which SUlTOUnds the 



abdominal aorta and other adjacent structures, and gives off 

 numerous small twigs to the neighbouring vessels and organs. 



b. Communications with the cranial nerves ; these are two 

 branches (Wiedersheim), (Figs, in and 116) which pass from the 

 first ganglion to the Ganglion nervi vagi, where one terminates, the 

 other leaves the ganglion to pass on to the Gasserian ganglion 



