We describe a new plain radiographic finding in posterior elbow disloc
ation: a defect in the nonarticular posterior surface of the capitellu
m caused by impaction of the radial head during dislocation. The defec
t was visible on a lateral view unobscured by overlying bony structure
s in the unreduced state and confirmed on both an axial view after red
uction and by magnetic resonance imaging. We propose that this lesion
is analogous to the Hill-Sachs/Bankart lesion complex seen in translat
ional glenohumeral injury.