Cardiac plexus

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The cardiac plexus is a plexus of nerves situated at the base of the heart. It is formed by cardiac branches derived from both the sympathetic and parasympathetic nervous systems.

Gross anatomy

Sympathetic cardiac nerves are derived from T1 to T4 segments and partly from the T5 segment of the spinal cord. They are the stimulators of cardiac function. Parasympathetic cardiac nerves reach the heart through the vagus nerve (cranial nerve X). They are inhibitors of cardiac function.

Superficial cardiac plexus

The superficial part of the cardiac plexus lies beneath the aortic arch, in front of the right pulmonary artery. It is formed by the superior cervical cardiac branch of the left sympathetic trunk and the lower superior cervical cardiac branch of the left vagus trunk. A small ganglion, the cardiac ganglion of Wrisberg, is occasionally found that forms a junction for these nerves.        

Branches
  • to the anterior coronary plexus
  • to the left anterior pulmonary plexus
  • to the deep part of the plexus
Deep cardiac plexus

The deep part of the cardiac plexus is situated in front of the tracheal bifurcation above the point of division of the pulmonary trunk (carina) and behind the aortic arch. It is formed by the cardiac nerves derived from the cervical ganglia of the sympathetic trunk and the cardiac branches of the vagus and recurrent laryngeal nerves except those that supply the superficial cardiac plexus.

Branches

The deep cardiac plexus can be divided into right and left halves. From the right half of the deep cardiac plexus, a branch passes in front of the right pulmonary artery and gives a few twigs to the anterior pulmonary plexus and then continues as a part of anterior coronary plexus. The branch passing behind the right pulmonary artery gives branches to the right atrium and then continues as a part of the posterior coronary plexus.

The left half is essentially connected with the superficial part of the cardiac plexus and gives twigs to the left atrium and to the anterior pulmonary plexus. It then continues to form the greater part of the posterior coronary plexus.