1. A case of epiphyseal separation of the lesser femoral trochanter is described.
2. The second case described, though clinically apparently similar to the first, showed no bony lesion in the roentgenograms and is interpreted as a partial rupture of the tendinous fibers of the iliopsoas muscle.
3. Cases of epiphyseal separation of the lesser femoral trochanter are quite rare, occurring mostly in boys between the ages of thirteen and seventeen, as a result of a sudden overexertion of the iliopsoas muscle, mostly during running.
4. Symptoms and signs of epiphyseal separation of the lesser femoral trochanter are pain and tenderness over the lesser trochanter, weakness or complete loss of flexion of the thigh, Ludloff's sign, and the peculiar "gait of deficient flexion of the thigh" observed in Case 1.
5. Treatment consists of rest in bed with relaxed iliopsoas muscle or immobilization by means of a plaster-of-Paris spica with the thigh in flexion, external rotation, and adduction; operative treatment is not justifiable.
6. Complete recovery with premature fusion of the epiphysis of the lesser femoral trochanter usually takes place in all cases.