A qualitative and quantitative study of the ventricles and great vessels of normal children

Abstract

1. 1. One hundred unfixed normal hearts were studied from children whose ages ranged from 6 months of intrauterine life to 12 years. Criteria of normality were established which were based on the anatomic and histologic examination of these hearts. All of the measurements obtained were analyzed statistically. 2. 2. The thickness of the walls of both ventricles increased with age. This increase in thickness was marked in the left ventricle and slight in the right ventricle. The wall of the right ventricle was always thinner than that of the left in the hearts of premature infants, in the hearts of newborn infants, and, in general, in all of the hearts studied. In the left ventricle the protion that reached the greatest thickness was the lateral border, and in the right ventricle the portion that was the thinnest was the anterior border. 3. 3. The study of the longitudinal growth of the ventricular outflow tracts showed that the largest tract as well as that which grew the most was the outflow tract of the right ventricle. The smallest tract and that which grew the least was the inflow tract of the same ventricle. 4. 4. The circumferences of the atrioventricular orifices, and the circumferences of the orifices of the great vessels increase with age. The circumference and the area of the tricuspid orifice were greater than those of the mitral orifice. The diameter and the circumference of the orifice of the pulmonary artery were greater than those of the aorta. 5. 5. The circumference of the trunk of the pulmonary artery and the circumference of the ascending portion of the arch of the aorta increase with age. The length of the trunk of the pulmonary artery also increases with age. In general, the circumference of the pulmonary artery was greater than that of the aorta. 6. 6. The length of the infundibulum of the pulmonary artery increases with age and in a manner parallel to the increase in the outflow tract of the right ventricle. The annulus of the valve of the pulmonary artery increased proportionally in relation to the inferior circumference of the infundibulum. The increase in the latter was 36 per cent greater than the increase in the valvular orifice of the pulmonary artery.