<prompt> Flexion of metacarpophalangeal joint and extension of interphalangeal joints is major action ofPalmar interosseiDorsal interosseiLumbricalsFDS  <response>: It is the action of lumbricals.The dorsal interossei abduct the fingers. the palmar interossei adduct the fingers.The FDS flexes middle phalanx at PIP joints. ref :textbook of anatomy upper limb and thorax ,vishram singh ,2nd edition ,page no.144 