The progressive muscular dystrophy (PMD) is an independent disease and so called one of the progressive muscular atrophy and dystrophy. Since 1968, the Japan Welfare Ministry have been started the study on the cause and treatment of PMD. This study was done a part of this project.

The study was made on the 51 PMD Patients using lateral head plate, plaster cast, and oral examnaition at Iwaki National Sanatorium. In majority an anterior open bite and posterior open bite were shown as a characteristic pattern and observed an exsistence of the cross bite of molar segment.

On the analysis of dental cast, inter molar distance on the mandibular arch was extermly wide, while arch length was shortenning oviously on the madibular.

According to the lateral head X-ray film, in many cases, observed steep mandibular plane, extensive Gonial angle and Gnathion came to downwards on the angular measurement, while cranial base and mandibular ramus were apparently undergrown on the liner measurement.

These findings suggested that there exists a definite correlation between a disorder of muscles and anomalies of Maxillo-facial bone structure.