Your wrist is the part of your body between your hand and your arm that bends when you move your hand.
e.g. Karen wore a bracelet on her wrist.
e.g. Susan sprained her wrist playing tennis.
The palm of your hand is the inside part of your hand, between your fingers and your wrist.
e.g. Jennifer held the bird gently in the palm of her hand.
e.g. Sarah lay down on the bed, resting her chin in the palm of her hand.
Your thumb is the short, thick finger on the side of your hand that makes it possible to hold and pick things up easily.
e.g. Carol stuck out a thumb and a car stopped immediately.
Your knuckles are the rounded pieces of bone that form lumps on your hands where your fingers join your hands, and where your fingers bend.
e.g. David clenched his right fist till his knuckles were white.
Your fingernails are the hard, slightly curved parts at the end of each of your fingers.
e.g. She cut the fingernail to the quick.