THORACIC PORTION OF THE SYMPATHETIC SYSTEM. 519 



to the tissue of the ventricles and auricles ; some follow the 

 divisions of the pulmonary artery, and assist in the formation of 

 the bronchial plexus ; and others, following the brachial arteries 

 and trachea, form, on the inferior face of the latter, a very large 

 fasciculus known as the tracheal plexus. This plexus is traversed 

 by the two recurrent nerves, which give and receive numerous 

 filaments as they pass. 



FIG. 196. 



Abdominal portion of sympathetic nerves viewed from the left side. 1 1, Posterior aorta ; 

 2, Liver ; 3, Stomach ; 4, Spleen ; 5, Anterior mesenteric nerves ; 5' 5', Small intestine ; 6, Left 

 kidney ; 7, Small mesenteric nerves ; 7', Floating colon ; a a, Sympathetic cord ; a' a', Union of 

 sympathetic and lumbar nerves ; a" a", Branches joining sympathetic and posterior mesenteric 

 plexus ; 6, Great splanchnic ; c, Semilunar ganglion ; rf, Hepatic plexus ; e, Gastric plexus ; /, Splenic 

 plexus ; g, Anterior mesenteric plexus ; h, Left renal plexus ; i, Posterior me*enteric plexus : 

 k, Left spermatic plexus. 



THORACIC PORTION OF THE SYMPATHETIC SYSTEM. 



The cord which represents the dorsal portion of the sympathetic 

 chain extends from the inferior cervical ganglion to the diaphragm, 

 crossing the intercostal arteries, and passing under the vertebro- 

 costal articulations, against which it is fixed by the pleura. 

 Passing through the arch at the superior border of the diaphragm, 



