| 1 abductor pollicis brevis muscle lateral end of flexor retinaculum lateral side of base of proximal phalanx abducts thumb reccurent branch of medial nerve superficial palmar branch of radial artery     2 flexor pollicis brevis muscle lateral end of the flexor retinaculum lateral side of base of proximal phalanx flexes thumb reccurent branch of medial nerve superficial palmar branch of radial artery   3 opponens pollicis muscle lateral end of the flexor retinaculum along shaft of 1st metacarpal "opposes" thumb (to pinky) reccurent branch of medial nerve superficial palmar branch of radial artery   4 adductor pollicis transverse - 2nd-4th metacarpal bones, oblique - capitate medial side of first phalanx of thumb adducts thumb deep branch of ulnar nerve (motor) deep palmar arch and its branches   EC 1-3: thenar compartment 4: adductor-interosseous compartment |