27 bones.
Each of the 4 medial fingers (thats any finger other than your thumb) has 3 phallenges, so you would have 12 phallenges. Plus 2 phallenges of the thumb that's 14.
We also have 5 metacarpals in each hand. The sum now is 19. With 8 carpals connecting the wrist to the hand we would have 27 bones in our hand and wrist!