Distribution of submucous gland in the human trachea, main and segmental bronchi: morphometric study.

A profile method of depicting the distribution of submucous gland in the human trachea and bronchi has recently been described from this laboratory. In that study the gland was assessed only in samples taken from the trachea and bronchi. The present study confirmed the validity of the sampling technique used by showing that the results obtained with it were representative of the amount of submucous gland as it varied throughout the whole length of the trachea and main bronchi in 1 case and around the trachea in a 2nd case. In addition the amount of gland in each of the 19 segmental bronchi of the 1st case was measured. This was found to be significantly less than the only previous measurements reported, probably because the effects of smoking in the latter were not taken into account. Nevertheless the present and previous measurements both show a previously unrecognised preponderance of gland on the right side at the segmental (generation 3/4) level, which could be related to the anatomy of the tracheobronchial tree.