Pain and tenderness over 5th metatarsal bone, esp. on weight-bearing; represents 2nd center of ossification detectable on radiographs in oblique view only. Condition occurs in girls at age of 10 years and boys at 12 years. Playing sports is precipitating factor; disease is often mistaken for fracture with nonunion of epiphyses. Treatment is rest, ice, NSAIDs, and (in severe cases) casting.