Cardiac ganglion is situated -

Ans. is 'a' i.e., Below arch of aortaNerve supply of hearto Nerve supply to the heart has both (i) Motor, and (ii) Sensory components.Motor componento Motor component includes parasympathetic and sympathetic systems, parasympathetic fibers reach the heart through vagus and are cardioinhibitory. Sympathetic fibers are derived from 7/ to Ts segment of spinal cord and are cardiostimu latory (excitatory). Both parasympathetic and sympathetic nerves form the superficial and deep cardiac plexues, the branches of which run along the coronary arteries to reach the myocardium.Superficial cardiac plexus Lies in front of right pulmonary artery' below the arch of aorta. It is fored by:-Superior cervical cardiac branch of the left sympathetic chain.Inferior cervical cardiac branch of left vagus.o A small ganglion, the cardiac ganglion of Wrisberg, is occaisonally found connected with these nerves at their point of junction. This ganglion, when present, is situated immediately beneath the arch of aorta, on right side of ligamentum arteriosum.Deep cardiac plexus Lies in fron of the bifurcation of trachea, behind the arch of aorta. It is formed by all sympathetic and parasympathetic cardiac branches except those forming the superficial plexus.Sensory componento Pain sensation arising due to ischemia is conveyed by afferents which pass through sympathetic cardiac fibers and reach the T1 to T5 cord segments on left side. Since these dorsal root ganglia also receive sensory impulses from the medial side of arm, forearm and upper part of front of chest, the pain gets referred to these areas through these thoracic splanchnic nerves (T1-T4). Though the pain is usually referred to the left side, it may even be referred to right arm, jaw, epigastrium, neck, shoulder or back.