ELBOW INJURIES IN THE THROWING ATHLETE

Most elbow injuries occur as a result of the stresses incurred during the acceleration phase of throwing. During overhead throwing, a large valgus force on the elbow created by humeral torque is countered by rapid elbow extension, creating substantial tensile stress along the medial compartment, shear stress in the posterior compartment, and compressive stress in the lateral compartment. Repetitive valgus loading resulting from overhead throwing in skeletally immature patients can lead to fragmentation or avulsion of the medial epicondylar apophysis. Injury to the flexor pronator mass can be traumatic or attritional, but before it is assumed that the injury involves the flexor pronator mass and will respond to conservative measures, injury to the ulnar collateral ligament must be ruled out.