Anterior paraseptal cartilage development in normal and cleft lip and palate human fetal specimens.

As part of an ongoing study of age-related variation in fetal cleft lip and palate nasal capsule morphology, anterior paraseptal cartilage development was examined histologically in a sample of nine complete cleft lip and palate human fetuses, and 20 without clefts ranging in age from 8 to 21 weeks. A computer reconstruction technique was used to quantify lengths, volumes, and generate growth curves from various regression equations. Anterior paraseptal cartilage length was seen to change in a sigmoidal fashion while volume changes were best described by a logarithmic curve for both groups, with the steepest increases from 15 to 21 weeks. Cleft specimens exhibited significantly different growth rates (line slopes) for both length and volume dimensions compared with the normal specimens. The larger, for age, cartilages were associated with an enlarged, inferior border of the nasal septal cartilage and vomer in the cleft sample. These results are consonant with previous findings in this cleft fetal sample of other enlarged midline structures (i.e., nasal septal cartilage and vomer). Results suggest that growth abnormalities in one or all of these structures may be yet another mechanism for early nasal airway impingement and reduction in cleft lip and palate neonates.