The |opponens pollicis| is a deep muscle. It is a small triangular muscle that lies just beneath the |abductor pollicis brevis|. It is part of the thenar eminence, the muscle mass of the thumb. The thenar eminence is a teardrop- or egg-shaped mass of muscles that constitutes the ball of the thumb. It consists of the |abductor pollicis brevis|, flexor pollicis brevis, and |opponens pollicis|.
