A longitudinal compression force on a growing long bone may cause partial or complete closure of a physis by crushing the germinal cell layer. In the absence of a fracture of the physis, the roentgenograms at the time of injury would be normal. This diagnosis can be made only in retrospect. To prove such a hypothesis, the following criteria would have to be met: normal findings on roentgenograms taken in at least 2 planes at the time of injury, no treatment and subsequent positive roentgenographic findings showing partial or complete closure of the physis, compared with the contralateral side. No cases that meet these criteria were found. Many other causes of premature closure of physes were well documented in the literature.