The position of the trachea in infants and children with right aortic arch.

In infants, the site of the aortic arch is frequently inferred from the position of the intrathoracic trachea. We retrospectively reviewed the plain frontal chest radiographs of 72 patients with cyanotic congenital heart disease and right aortic arch documented by cardiac catheterization. In infants, the position of the trachea was variable: 47% had the trachea on the right, 33% had the trachea midline and in 7% the trachea was on the left. As the child grows, the aortic arch progressively indents the trachea, and the descending aorta is better visualized. Since the position of the trachea in infants with right aortic arch is variable, one must be cautious in inferring the site of the aortic arch by the position of the trachea.