968 A MANUAL OF ANATOMY 



the trachea above the bifurcation and behind the aortic arch. It is 

 formed by branches of the pneumogastric and sympathetic nerves, 

 and consists of two portions, superficial and deep, which communicate 

 with each other. 



The superficial cardiac plexus, which is comparatively small,, is 

 situated in the concavity of the arch of the aorta, between the 

 ligamentum ductus arteriosi and the right pulmonary artery. It 

 is formed by (i) the superior cervical cardiac branch of the left 

 sympathetic, and (2) the inferior cervical cardiac branch of the left 

 pneumogastric, nerves. These two nerves descend over the arch 

 of the aorta, lying between the left phrenic and left pneumogastric 

 nerves. At the place where the two nerves join there may be a 

 small ganglion, which is known as the ganglion of Wrisberg. 



Branches. — ^The plexus gives branches to the left anterior pul- 

 monary plexus, and, having received a considerable accession of 

 fibres from the right half of the deep cardiac plexus, it is prolonged 

 into the right coronary plexus. 



The deep cardiac plexus, of larger size than the superficial, is 

 situated upon the trachea immediately above the bifurcation and 

 behind the arch of the aorta. It is formed by (i) all the cervical 

 cardiac branches of the right sympathetic, namely, superior, middle, 

 and inferior, and of the right pneumogastric, namely, superior and 

 inferior ; (2) one or two cardiac branches from the right recurrent 

 laryngeal nerve ; (3) one or two thoracic cardiac branches from the 

 right pneumogastric ; (4) the middle and inferior cervical cardiac 

 branches of the left sympathetic ; (5) the superior cervical cardiac 

 branch of the left pneumogastric ; and (6) the thoracic cardiac 

 branches of the left recurrent laryngeal nerve. It is arranged in 

 two halves, right and left, which communicate with each other ; 

 the right half also gives a considerable accession of fibres to the 

 superficial cardiac plexus. Each half receives the following 

 branches : 



Right Half. Left Half. 



1. The three cervical cardiac i. The middle and inferior cervical 



branches of the right sympa- cardiac branches of the left 



thetic. sympathetic. 



2. The two cervical cardiac 2. The superior cervical cardiac 



branches of the right pneumo- branch of the left pneumo- 



gastric. gastric. 



3. The cardiac branches of the 3. The cardiac branches of the 



right recurrent laryngeal. left recurrent laryngeal. 



4. The thoracic cardiac branches 



of the right pneumogastric. 



Branches. — ^The right half of the deep cardiac plexus gives off 

 (i) branches to the right anterior pulmonary plexus ; (2) branches 

 to the right auricle of the heart ; (3) branches to reinforce the right 

 coronary plexus, which is deprived, as stated, from the suj^erficial 

 cardiac plexus ; and (4) a few branches to the left coronary plexus. 

 The left half of the deep cardiac plexus gives off (i) brcinches to the 



