Body surfing as a cause of luxatio erecta: report of four cases.

True inferior dislocation of the shoulder (luxatio erecta) is a rare type of shoulder dislocation. It is caused by hyperabduction of the arm while in the overhead position. We report four recent cases, all of which occurred while body surfing. All of the individuals in this report were struck by a wave with their arms in the overhead position and their arms were forced into the sand.