Two cases of spontaneous bilateral volar-radial deviation of the terminal phalanges of the little fingers (Kirner's disorder) are reported. The first case was accompanied by digital pain, and the second was associated with progressive myositis ossificans. Typically, the disorder occurs in the prepubescent child. The clinical course and roentgenographic appearance suggest that the lesion is the result of a defect in enchondral ossification on the volar aspect of the epiphyseal plate and slipping of the epiphysis.