Nine children with Apert's syndrome were studied and found to have pro
gressive bony dysplasia in the shoulder and elbow. The children showed
loss of joint motion and radiographic abnormalities including subluxa
tion and flattening of the humeral head with irregularities of the gle
noid. The elbow showed flattening and subluxation of the radial head i
n radiographs and a positive click on physical examination. The limita
tion of motion and the presence of bony defects were progressive, sugg
esting that Apert's syndrome is a progressive generalized dysplasia.