Abstract

The coronary arteries of young individuals are histologically studied. Fourteen cases in pediatric age group and three adult hearts were used. No case had clinical and pathological evidences of heart disease. Inner circumference, thickness of tunicae intima, media and adventitia were measured at eight different sites of coronary arteries. The thickness of tunica media was used as a standard scale of cardiac growth, and the heart weight, body weight, height and age were compared with the medial thickness. The morphological changes were assessed in five groups by the heart weights. Group I ( less than 10 gm) showed single endothelial lining with cytoplasmic vacuolization or endothelial denudation. Group II (more than 10 but less than 20 gm) consisted of full term babies and showed first stigma of focal intimal thickening and intimal collagen fibers. Diffuse intimal thickening more than 1/1 of medial thickness was first seen in a case with 46 gm of heart weight. Elastic fiber was not seen in internal elastic laminae of groups I and II. Fragmentation of internal elastic lamina and smooth muscle proliferation as a form of musculoelastic layer were the major findings of intimal thickening in childhood and no case showed complicated atherosclerotic lesions.