[TA] muscle of posterior (extensor) compartment of forearm; origin, lateral epicondyle of humerus; insertion, dorsum of proximal, middle, and distal phalanges of little finger; action, extends little finger; nerve supply, radial (posterior interosseous). SYN: musculus extensor digiti minimi [TA], extensor (muscle) of little finger, musculus extensor digiti quinti proprius, musculus extensor minimi digiti.