The inferior cardiac nerve (lat. n. cardiacus inferius) is an unpaired, right and largest of the upper cardiac nerves (sympathetic nerves innervating the heart). Function: Transmission of impulses from the neurons of the lateral horns of the spinal cord and the sympathetic plexuses of the branches of the spinal nerves to the heart. Provides myocardial tone. In humans, the vagus nerve takes part in the formation of its branches. The basis for dividing the nerve plexus in the pericardial space into two sections - upper and lower - was given by the French scientist Santon Dizard in 1729. The upper sympathetic nodes are called in Latin - cardiac, or cardiac plexus (cardiacus).