Stress fracture of the ipsilateral first rib in a pitcher.

This stress fracture of the left first rib in a 17-year-old, left-handed high school baseball pitcher represents the first of its type reported in the literature. Two similar cases have been reported in pitchers, but the fracture was on the nondominant side in both cases. In contrast to most cases of this rare lesion, the stress fracture we report occurred acutely and was documented roentgenographically from onset to complete healing 9 months later.