300 



THE CIRCULATION IN THE BLOOD-VESSELS [CH. XXI. 



along the sympathetic trunk to their destination. Their cell station 

 is in the superior cervical ganglion. 



Those for the body wall and limbs pass back from the sympathetic 

 ganglia to the spinal nerves by the grey rami communicantes, and are 

 distributed with the other spinal nerve-fibres. The cell stations for 

 the upper limb fibres are in the ganglion stellatum, and for the lower 

 limb fibres in the lower lumbar and upper sacral ganglia. 



Those for the interior of the body pass into the various plexuses 



FIG. 297. Transverse section through half the spinal cord, showing the ganglia. A, anterior cornual 

 cells ; B, axis-cylinder process of one of these going to posterior root ; C, anterior (motor) root ; D, 

 posterior (sensory) root; E, spinal ganglion on posterior root ; F, sympathetic ganglion; G, ramus 

 communicans ; H, posterior branch of spinal nerve ; I, anterior branch of spinal nerve ; a, long 

 collaterals from posterior r&ot fibres reaching to anterior horn; b, short collaterals passing to 

 Clarke's column; c, cell in Clark's column sending an axis-cylinder (d) process to the direct cere- 

 bellar tract ; e, fibre of the anterior root ; /, axis-cylinder from sympathetic ganglion cell, dividing 

 into two branches, one to the periphery, the other towards the cord ; g, fibre of the anterior root 

 terminating by an arborisation in the sympathetic ganglion ; h, sympathetic fibre passing to peri- 

 phery. (Ramon y Cajal.) 



of sympathetic nerves in the thorax and abdomen, and are distributed 

 to the vessels of the thoracic and abdominal viscera. This set includes 

 the most important vaso-motor nerves of the body, the splanchnics. 

 Their cell stations are situated in the various ganglia of the abdominal 

 plexuses. 



The vaso-dilator nerves in part accompany those just described, 

 but they are not limited to the outflow from the second thoracic to 

 the second lumbar. Thus, the nervi erigentes originate as white 



