ANTERIOR PARASEPTAL CARTILAGE DEVELOPMENT IN NORMAL AND CLEFT-LIP ANDPALATE HUMAN FETAL SPECIMENS

As part of an ongoing study of age-related variation in fetal cleft li p and palate nasal capsule morphology, anterior paraseptal cartilage d evelopment was examined histologically in a sample of nine complete cl eft lip and palate human fetuses, and 20 without clefts ranging in age from 8 to 21 weeks. A computer reconstruction technique was used to q uantify lengths, volumes, and generate growth curves from various regr ession equations. Anterior paraseptal cartilage length was seen to cha nge 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 gro wth rates (line slopes) for both length and volume dimensions compared with the normal specimens. The larger, for age, cartilages were assoc iated with an enlarged, inferior border of the nasal septal cartilage and vomer in the cleft sample. These results are consonant with previo us findings in this cleft fetal sample of other enlarged midline struc tures (i.e., nasal septal cartilage and vomer). Results suggest that g rowth abnormalities in one or all of these structures may be yet anoth er mechanism for early nasal airway impingement and reduction in cleft lip and palate neonates.