Complete tear of ulnar collateral ligament of the metacarpophalangeal joint of thumb at its insertion over the base of proximal phalanx. The retracted ulnar collateral ligament appear thickened.
The torn ulnar collateral ligament is seen overlying the tendon of adductor pollicis. Edema noted in the tendon of adductor pollicis at this level – suggestive of stener lesion.