Dimensions & shape of the trachea in the neonates, children & adults in northwest India.

Measurements of the trachea and the two main bronchi including the subcarinal angle and the angles of the bronchi with the vertical were taken in specimens obtained from 370 adults, 60 children and adolescents up to 17 yr and 27 dead newborns. These measurements showed a gradual increase with age up to a certain point (often 31-35 yr in males and 26-30 yr in females) and stabilised thereafter. There was no sexual dimorphism in measurements till the age of 17 yr and thereafter, the measurements were greater in males than in females (P < 0.001). In adults the body weight and supine body length had a significant correlation with certain measurements of the trachea. The subcarinal angle and the angles of the two main bronchi with the vertical were variable but the angle of the right bronchus with the vertical was always found to be smaller than that of the left. The incidence of different shapes of the trachea at transversely cut upper end was also studied. A U-shaped trachea was present in 33.2 per cent male adults but was not seen in females. This may have some medico-legal importance.