"A deep-seated muscle; specifically the flexor digitorum profundus muscle, which arises from the ulna, flexes the distal phalanges of the fingers, and is situated beneath the muscle which flexes the middle phalanges", Late 17th cent. From classical Latin profundus (originally in post-classical Latin or scientific Latin musculus profundus).[profundus etymology, profundus origin, 英语词源]