[Simultaneous functional bilateral radiographies of the metacarpophalangeal joint of the thumb in hyper-pronation].

Diagnosis of tears of the ulnar collateral ligament of the metacarpophalangeal joint of the thumb is often made by dynamic radiography. In contrary to the usual technic, the best position is forced pronation of the hand. The metacarpal and the first phalanx are horizontal on the X ray plate. The patient is encouraged to push the tip of his thumb against an object thus obtaining a forced abduction. The two hands can be held in place with a tight bandage. This yields a simultaneous and symmetrical image of the two thumbs on the same film.