Radiological sign of recurrent dislocation of the patella.
D000328:Adult; D005260:Female; D006801:Humans; D004204:Joint Dislocations / Q000000981:diagnostic imaging; D007718:Knee Injuries / Q000000981:diagnostic imaging*; D008297:Male; D009999:Ossification, Heterotopic; D010329:Patella / Q000000981:diagnostic imaging*; D011859:Radiography