Opponens policis m

One of the 3 thenar muscles (the deepest of the three), the opponens pollicis pulls the base of the thumb medially and anteriorly, so that it comes to lie anterior to the palm of the hand.  It originates from the trapezium and the transverse carpal ligament, and inserts into the 1st metacarpal bone (thumb).  It is innervated by the recurrent median n.  Note that the flexor and abductor pollicis brevis have been reflected in the image.