Our aim in the present study was to determine some of the changes which occur in the size and shape of the cardiac silhouette and the thoraco-abdominal cavity from birth until the end of the first year and to define their relations to some of the external body dimensions. Measurements of the heart and thoraco-abdominal cavity were made from roentgenograms. The external dimensions were measured by a technic previously described.1 Means and standard deviations, which measure the extent of departures from the mean, were calculated.
MATERIAL AND METHOD
The infants used in this study (165 boys and 146 girls) were born in Bellevue Hospital and came for the most part from very poor homes. After being discharged from the maternity wards, they were supervised in a special clinic devoted to the care of well infants. These infants grew normally, averaging 739 mm. in height and 9,500 Gm. in weight