Dynamic Ulnar Drift of Single Digit by an Anomalous Accessory Extensor Tendon.

Descriptions of multiple extensor slips and accessory extensor tendons of the hand are extensively published in the contemporary literature. Despite their varied anatomy, accessory tendons seldom have a functional implication for the patient. We report a case detailing a previously undescribed accessory extensor tendon of the hand, which resulted unusually in an aberration in the mechanics of a single digit. This was explored and corrected surgically, resulting in an excellent outcome for the patient.