become weakened from repetitive microtrauma ( Fig 121.10 ) Little Leaguer elbow occurs most commonly in boys aged to 12 years Patients complain primarily of elbow pain that is exacerbated by throwing Athletes report progressive drop off in throwing distance Tenderness is localized over the medial elbow Applying a valgus stress to the partially flexed elbow will reproduce the pain Flexion of the wrist or fingers against resistance will also elicit pain In advanced cases, extension of the elbow becomes limited Radiographs or MRI may reveal nonspecific changes such as an irregular or widened medial epicondylar physis ( Fig 121.11 ), but in general an apophysitis is not visible Any abnormalities should be correlated with clinical findings to distinguish normal musculoskeletal adaptation to stress from pathologic injury An avulsion fracture may appear as a bony fragment separated from the medial epicondyle Comparison views of the nonthrowing elbow may confirm asymmetric changes