Is it possible for Wolverine style retractable bone claws, to work in real life? Either from the knuckles, or from the wrist (hidden blade style). How would such claws, if possible, change the appearance of the person? 

If not Wolverine claws, then what other retractable claw designs are feasible in reality? What about shorter and thinner versions of Baraka's claws? <https://upload.wikimedia.org/wikipedia/en/thumb/4/44/BarakaMK9render.png/220px-BarakaMK9render.png>

Or a single claw extending from below the wrist? Doesn't have to be too long. Like the hidden blade from Assassin's Creed.