[TA] thenar muscle of palm; origin, medial surface of cuboid and middle and lateral cuneiform bones; insertion, by two tendons, embracing that of the flexor longus hallucis, into the sides of the base of the proximal phalanx of the great toe; action, flexes great toe; nerve supply, medial and lateral plantar. SYN: musculus flexor hallucis brevis [TA], musculus flexor brevis hallucis, short flexor (muscle) of great toe.