Power grip of hand depends on?

in power grip ,4 finger pulps are opposed to thenar eminence.the thumb base and thenar pad provide fixed buttress.The MCP joints of other fingers are flexed by the interossei and lumbricals. Long flexors flex PIP joints but the DIP is flexed by Flexor digitorum profundus alone. The profundus is more impoant in power grip and the ulnar nerve too as it supplies the FDP. The contraction of palmaris brevis imroves grip. Reference: Clinical Anatomy for students: a problem-solving approach, Neeta v Kulkarni,1st edition, pg no.106