Shin splint: An inflammatory condition of the front part of the tibia (the big bone in the lower leg) that results from overuse, as, for example, from running too much on hard roads or sidewalks. Shin splints are due to injury to the posterior peroneal tendon, ligaments, and adjacent tissues in the front (anterior) of the leg. The pain from shin splints is usually noticed early in exercise, then it lessens, and then it reappears later, during running or other activity. Characteristically, the pain is dull at first but intensifies with continuing trauma. Treatment involves a multifaceted approach of 'relative rest' and stretching exercises to restore the person to a pain-free state.