Tracheobronchial gland profiles in four segmental airways.

Previously described methods of measuring the amount of submucous gland in the trachea and bronchi have various disadvantages. These have been overcome by a method in which area point counting has been used to obtain a new unit, Vgl mm3/mm2, the volume of gland per unit airway surface area; Vgl has been obtained for the trachea, the main and lobar bronchi, and for successive airway generations down 4 segmental bronchi (the left lingular , the left anterior basal, the right middle medial, and the right anterior basal) from 3 nonsmokers, and presented in profile form. The profiles have a distinctive shape, not previously appreciated, with a rise to a proximal peak and then a striking fall to low Vgl values in the subsegmental bronchi. The shape of the profile is intriguing, but at present the information required to answer the questions it raises is not available. As there were no significant differences between the profiles of the 4 airways in the individual subjects, any one of the 4 airways may be chosen to give a representative profile for an individual subject.