Power grip of hand is a function of
Power grip is by extrinsic muscles of hand which originate in the forearm and inse in the hand - Long flexors Precision grip is a function of the intrinsic muscles of hand which originate and inse in the hand. Ref: Gray's Anatomy The Anatomical Basics of Clinical Practice 41 e pg 860.
Long flexors
Sho flexors
Palmaris brevis
Lumbricals
Upper limb