698 THE SYMPATHETIC NERVES. 



B. THE GREAT PLEXUSES OF THE SYMPATHETIC. 



Under this head may be included certain large plexuses of nerves placed 

 further forwards in the visceral cavity than the gangliated cords, and 

 furnishing branches to the viscera. The principal of these plexuses are the 

 cardiac, the solar, and the hypogastric with the pelvic plexuses prolonged 

 from it. They are composed of assemblages of nerves, or of nerves and 

 ganglia, and from them smaller plexuses are derived. 



CARDIAC PLEXUS. 



This plexus receives the cardiac branches of the cervical ganglia and those 

 of the pneumo-gastric nerves, and from it proceed the nerves which supply 

 the heart, besides some oifsets which contribute to the nervous supply of 

 the lungs. It lies upon the aorta and pulmonary artery, where these vessels 

 are in contact, and in its network are distinguished two parts, the superficial 

 aud the deep cardiac plexuses, the deep plexus being seen behind the vessels, 

 and the superficial more in front, but both being closely connected. The 

 branches pass from these plexuses chiefly forward in two bundles, accom- 

 panying the coronary arteries. 



SUPERFICIAL CARDIAC PLEXUS. 



The superficial cardiac plexus lies in the concavity of the arch of the 

 aorta, in front of the right branch of the pulmonary artery. In it the 

 superficial or first cardiac nerve of the sympathetic of the left side termi- 

 nates, either wholly or iu part, together with the lower cardiac branch of 

 the left pneumo-gastric nerve, and in some cases also that of the right 

 side. In the superficial plexus a small ganglion, the ganglion of Wrisberg, 

 is frequently found at the point of union of the nerves. Besides ending in 

 the anterior coronary plexus, the superficial carliac furnishes laterally 

 filaments along the pulmonary artery to the anterior pulmonary plexus of 

 the left side. 



DEEP CARDIAC PLEXUS. 



The deep cardiac plexus, much larger than the superficial one, is placed 

 behind the arch of the aorta, between it and the end of the trachea, and 

 above the point of division of the pulmonary artery. 



This plexus receives all the cardiac branches of the cervical ganglia of the 

 sympathetic nerve, except the first or superficial cardiac nerve of the left 

 side. It likewise receives the cardiac nerves furnished by the vagus and by 

 the recurrent laryngeal branch of that nerve, with the exception of the 

 left lower cardiac nerve. 



Of the branches from the right side of the plexus, the greater 

 number descend in front of the right pulmonary artery, and join branches 

 from the superficial part in the formation of the anterior coronary plexus, 

 while the rest, passing behind the right pulmonary artery, are distributed 

 to the right auricle of the heart, and a few filaments are continued 

 into the posterior coronary plexus. 



On the left side, a few branches pass forwards by the side of the ductus 

 arteriosus to join the superficial cardiac plexus ; but the great majority 

 end in the posterior coronary plexus. 



The deep c.trdiac plexus sends filaments to the anterior pulmonary plexus 

 on each bide. 



