Growth mechanisms in skulls with facial clefts. Descriptive and experimental studies on the facial skeleton

During postnatal growth, skulls of patients with untreated unilateral clefts of the alveolus and palate develop additional anomalies of the facial skeleton. Similar anomalies--a deviation of the upper jaw to the non-cleft side and retropositioning of the maxilla on the cleft side--develop in rabbits with the same type of cleft, surgically produced in the fourth week after birth. Based on a quantitative study of the postnatal growth of the rabbit skull under normal and various experimental conditions, a mechanisms is proposed for the late developement of anomalies of the facial skeleton in cleft-affected skulls.