THE NERVES. 427 



the first to the third ganglion, upon the heads of the ribs, then 

 more externally), through the thorax, and divided, between the 

 external and middle crus of the diaphragm, into the abdomen. 

 Before it is covered by the pleura; behind it pass the vasa and 

 nerv. intercost. ; close to that of the right side the v. azygos. Its 

 ganglia : 



Ganglia thoracica (eleven to twelve) are flat, generally tri- 

 angular, with the apex directed outwards, and they are applied 

 to the outer side of the trunk. The two first and the twelfth 

 are the most developed, but less so than the cervical ganglia. 

 The first is covered, partly, by art. subclavia and vertebral. 

 They contain a single or threefold root from the intercostal 

 nerves, and give branches : to the cardiac, pulmonary, ceso- 

 phageal, and aortic plexuses, for the bodies of the vertebrae 

 and the intercostal spaces. Lastly : 



The roots to the nervi splanchnici, the visceral branches. 



676. III. Pars lumbalis n. sympatkici. 



The lumbar portion descends on the sides of the bodies of the 



lumbar vertebrae internal to the m. psoas, and unites above and 



below by means of transverse cords with the one of the other side. 



The trunk is single as well as double and triple. Its ganglia : 



Ganglia lumbalia (four to five) are small, flat, and elongated, 



frequently blending one with another, so that only two or 



three appear to be present (as in the neck) ; grayish-red, like 



the rest of the ganglia, and lying on the left behind aorta 



abdominalis, on the right behind v. cava. Their single, 



double, triple or five-fold roots, from the anterior branches of 



the lumbar nerves, are very long, and pass into them, around 



the bodies of the vertebra?, under m. psoas. Branches : 



To aorta abdominalis, artt. lumbales, kypogastrica, and the 



plexuses of the same names, n. renalis infer., poster., and 



filaments between n. renalis and spermaiicus. 



677. IV. Pars sacralis et coccygeus. 



The pelvic portion descends, divided into two larger filaments, 

 on the anterior surface of the sacrum, to the inner side of foram. 

 sacralia anteriora. Its trunk is very delicate, approaches more 

 and more the farther it descends to that of the other side, and 

 unites by means of transverse filaments with it, and the plexus 

 about the art. sacralis media, and terminates with the gangl. coc- 

 cygeum. Its ganglia : 



