Thumb sprain, ulnar collateral ligament Note that the examination is limited secondary to motion artifact affecting the axial sequences.There is abnormal signal intensity and decreased caliber of the ulnar collateral ligament, particularly dorsally, suggesting prior tearing which is at least partial in nature (series 7, images 6 and 7 of 16). There is no surrounding soft tissue or marrow edema along the ulnar aspect of the thumb to suggest an acute injury. The radial collateral ligament is intact.There is increased marrow signal within the distal phalanx of the thumb as well as the head of the proximal phalanx. There is also increased signal of the surrounding soft tissues however on STIR sequences, these signal abnormalities are absent and as a result, they're thought to be artifactual in nature. There is however a small amount of edema within the flexor pollicis brevis muscle although the remaining musculature of the visualized hand and thumb is normal.
1. Findings suggestive of remote ulnar collateral ligament injury with abnormal signal intensity and decreased caliber of the ligament particularly dorsally.2. Mild edema of the flexor pollicis brevis muscle.