opponens pollicis (muscle)

op·po·nens pol·li·cis (mus·cle)

[TA] thenar muscle of palm; origin, ridge of trapezium and transverse carpal ligament (flexor retinaculum); insertion, anterior surface of the full length of the shaft of the first metacarpal bone; action, acts at carpometacarpal joint to "cup" palm, enabling one to oppose thumb to other fingers; nerve supply, median. Synonym(s): musculus opponens pollicis [TA], opposer (muscle) of thumb