344 



THE GEEAT SYMPATHETIC. 



The phrenic eluded in the group now under consideration, yet, considering 

 nerve. its important connection with the motions of respiration, it is 



proper to describe and illustrate it here. 



It arises from the third and fourth cervical nerves, aided by a branch 

 from the fifth, or from the brachial plexus, and from the sympathetic. 

 In its descent it communicates with the lower cervical ganglion, enters 

 the thorax between the subclavian vein and artery, and, passing along 

 the side of the pericardium, descends to the diaphragm, the right phrenic 

 being perpendicular, and the left running obliquely round the apex of the 

 heart. It is distributed, for the most part, to both faces of the diaphragm, 

 superior and inferior. It is the motor nerve of the diaphragm. 



Fig. 174 



The phrenic nerve. 



ILLUSTRATION OF THE PHRENIC NERVE. 



Fig. 174: 1,1, root of the phrenic 

 nerve, furnished by the fourth cervi- 

 cal ; 2, 2, roots from the brachial 

 plexus ; anastomosis of this nerve 

 with branch of the subclavian ; 4, 

 anastomosis with the inferior cer- 

 vical ganglion ; 5, 5, curve of the 

 hypoglossal, cut, sending a twig to 

 the phrenic nerve ; 6, 6, pericardiac 

 branches of the phrenic nerve ; 7, 

 7, branches to the superior face of 

 the diaphragm; 8, 8, branches to 

 the inferior face of the diaphragm ; 

 9, anastomoses . of these branches 

 with, 10, the solar plexus ; 11, 

 transverse communication of the 

 phrenic nerves. 



OF THE GREAT SYMPATHETIC NERVE. 



Under the designations of sympathetic, visceral, toisplanchnic, gangli- 

 Position and on * c ' i ntercosta ^ or nerve of organic life, passes a series of 

 structure of the reddish or gray ganglia, interconnected by nervous strands, 

 sympathetic, extending along each side of the vertebral column, from the 

 head to the coccyx, communicating with all other nerves of the body, 

 and distributing branches to the internal viscera, or organs of involunta- 

 ry function. These ganglia are less numerous than the vertebrae ; the 

 chain on each side communicates with its colleague through plexuses, 

 and the ganglion impar is the common uniting point on the coccyx be- 

 low. By some it is supposed that the ganglion of Ribes, and by others 

 that the pituitary body has the same function in the cranium above. 



