Hand Position for Playing Piano
The Strong Muscles
The muscles on the underside of the arm and hand are your strong muscles. These are the muscles that move your hand and arm down.
These are the muscles that we want to use when we play piano. In other words, your fingers should be curved down when you play.
The Weak Muscles
The weak muscles of your arms and hand are the muscles on top of the arm and hand. These are the muscles that move your arm and hand up. These muscles are not strong enough to take much pressure.
If you put pressure on your fingers from the bottom with fingers extended or flat over a substantial period of time, your fingers will get hyperextended or curved up or bent up. This is permanent bone damage.
Test Your Fingers
Open your hand and extend your fingers. When your hand is extended, normally your fingers should be straight. This is what is normal and correct. If they are curving up, you have permanent bone damage.You can get this permanent bone damage from using flat fingers and putting pressure on the pad of your fingers from below, rather than curving your fingers down and using the tips of your fingers.