Sagittal growth trends of the development of cleft palate in mice homozygous for the "paddle" gene.

Paddle is a lethal, single recessive gene mutation in the mouse which results in a large median cleft palate and chondrodystrophy. Comparative cephalometric measurements on the growth of the normal and paddle fetal craniofacial complexes were made to determine the cause of cleft palate in paddle. Two methods of cephalometric measurements were used with 20 parameters analyzed. Both methods revealed a reduction in maxillary and mandibular growth, and a reduced cranial base angle which did not allow forward movement of the tongue under the primary palate, and hence obstructed shelf movement.