A quantitative coronal plane evaluation of craniofacial growth and spatial relations during secondary palate development in the rat

Abstract

Movement of the lateral palatine processes from the vertical to the horizontal plane occurs in a complex three-dimensional environment. Selected coronal sections of foetal Sprague-Dawley rat heads were magnified and measured. Mean group outlines were mapped and graphic composite illustrations made to demonstrate relative changes. During the two-day period about the time of palatal closure, although the height of the oro-nasal cavity doubled, there was little change in the width. As the height increased, the position of the tongue became lower relative to the palato-maxillary processes and a space developed above the tongue in the middle-palate region. During shelf elevation, the width of the oral cavity and the maxilla decreased, but the vertical dimension was unchanged.