638 THE SYMrATHETIC XERVES AXD GAXGLIA. 



THE GREAT PLEXUSES OP THE SYMPATHETIC. 



Under this head may be included certain large plexuses of nerves 

 placed further forwards "in the visceral cavity tlian 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 offsets 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 dis- 

 tinguished two parts, the superficial and the deep cardiac plexuses, the 

 deep plexus being seen behind the vessels, and the superficial more in 

 front, but both being closely connected. Tlie branches pass from these 

 plexuses chiefly forward in two bundles, accompanying 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 terminates, either wholly or in 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 Wrisherg, is frequently found at the 

 point of union of the nerves. Besides ending in the anterior coronary 

 plexus, the superficial cardiac plexus furnishes laterally filaments along 

 the pulmonary artery to the anterior pulmonary plexus of the left side. 

 Eeep 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 pul- 

 monary 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 rigJit side of the plexus, the greater number 

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

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

 while the rest, passing behind the right pulmonary artery, are distri- 

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

 into the posterior coronary plexus. 



On the Jpft 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 cardiac plexus sends filaments to the anterior pulmonary 

 plexus on each side. 



Coronary Plexuses. — The anterior coronary plexus, formed at fii'st from the 

 fibres of tlic superficial cardiac plexus, passes forwards between the aorta and 



