Abstract
Development of the laryngeal mucosa and its relationship to the appearance of glandular distribution was studied by examining the changes in the laryngeal structures at the level of subglottic larynx of 55 human infants. By making a transverse section at the level of cricoid cartilage, the area and diameter of each subglottic structure were examined using an image analysis system. The results were analyzed not only by their age at birth, but also based on the Total Development Score (TDS) that was estimated by adding the age at death and the gestational period. The areas of the whole structure, cricoid ring, maximum airway, subglottic mucosa and inner cavity (available airway) increased in close correlation with the TDS. In contrast to the increased diameter of the inner cavity, the thickness of the mucosa was almost the same size. The area occupied by the glands increased according to TDS. These results indicate the stability of the subglottic airway with advancing age and, also, the local defense system by glandular tissues develops constantly after birth.
