The muscles of the hand can be intrinsic (located within the hand) or extrinsic (originate outside the hand and insert within it).
The forearm muscles that control the actions of the wrist, hand, thumb and fingers are extrinsic hand muscles.
The hypothenar eminence is a group of three intrinsic hand muscles, the "digiti minimi" that control the motion of the little finger.
Those muscles are: the abductor digiti minimi, the flexor digiti minimi brevis, and the opponens digiti minimi.
The palmaris brevis is a thin muscle that arises from the palmar aponeurosis and inserts into the skin of the palm.