630 



SYMPATHETIC NERVE. 



one in number, pass obliquely upward and outward to join 

 the corresponding spinal nerve, though a twig is sometimes 

 sent to the intercostal FIG. 202. mediastinum, following 

 nerve below. The in- 

 ternal branches consist 

 of the mediastinal and 



splanchnic. The for- 

 mer enter the posterior 



the course of the inter- 

 costal arteries to the aor- 

 ta on both of which they 

 ramify in the form of 

 plexuses. Other branch- 

 es are traced upon the 

 oasophagus, the longus 

 colli muscle, and into the 

 cardiac and pulmonary 

 plexuses. The splanchnic nerves 

 are divided into the great and 

 less. The great splanchnic comes 

 from the sixth, seventh, eighth, ninth 

 and tenth ganglia, by several distinct 

 roots. These descend obliquely upon the 

 sides and front of the dorsal vertebrae, to 

 about the tenth or eleventh, where they 

 unite into a common trunk, which is large 

 and passes through the diaphragm either 

 by piercing it, or along with the aorta to 

 terminate in the semilunar ganglion. The lesser splanchnic 

 derives its roots from the tenth and eleventh ganglia. 

 These roots, uniting, enter the abdomen through the crus 

 of the diaphragm, external to the great splanchnic, and go 

 to the renal plexus. 



The sympathetic nerve in the abdomen (Fig. 155) com- 

 prises the semilunar ganglion and its various plexuses, with 

 the lumbar ganglia. 



The semilunar ganglion is situated upon either side of 

 the coaliac artery, and by some is regarded as the grand 



FIG. 202 represents the connection of the Sympathetic Nerve with the 

 Spinal, a a Anterior fissure of the spinal marrow 6 Motor or anterior root 

 of the spinal nerve, c Posterior root, d Ganglion on the posterior root. // 

 Spinal nerve, e Its posterior branch, g Its anterior hranch. h h Two tho- 

 racic ganglia of the sympathetic, i Sympathetic trunk connecting the ganglia. 

 j fc Two filaments uniting the sympathetic and spinal nerve. 



