The right paratracheal stripe in children.

The width of the right paratracheal stripe (RPS) has been established in normal adults but not in normal children. The thymus and great vessels are relatively larger in children than in adults and could obscure or widen the RPS. We found that obscuration does occur and, therefore, the RPS is less often measurable in children than in adults. Widening by the thymus and great vessels, however, does not occur. The width of the RPS in normal children, 0.5 to 3.0 mm, is slightly less than in adults. From this study of normal children and our subsequent experience with pediatric patients, we conclude that in a child an RPS 4 mm or wider is reliable evidence of disease affecting the trachea, mediastinum, or pleura.