A case of anterolateral first rib fracture produced by indirect trauma in a surfer is presented. A 17-year-old man was seen in the emergency department with the complaint of left shoulder pain that developed while he performed a so-called lay back maneuver on a surfboard. No history of direct trauma was elicited. After physical examination revealed point tenderness high in the left axilla, radiographic evaluation of the chest showed an isolated fracture of the anterolateral aspect of the left first rib. No morbidity was associated with this fracture which, when produced by other forces, can have serious sequelae.