Thursday, April 3, 2014

Finger Play, Part Two

I am a big fan of the 1951 movie version of Dickens' A Christmas Carol. I've seen most of the other versions, but I still prefer this one, thanks to Alistair Sim's portrayal of the cranky old miser who becomes as good a man as Victorian London could imagine. One of my favorite scenes is the visitation of the Ghost of Christmas Yet to Come. He shows up in a dark, hooded cloak, and all that is visible is his bony right hand, jutting out from a draping sleeve as he points to Scrooge's future headstone. That hand is downright creepy!

Bony hands often look extremely long because they show all the bones of the fingers. It is easy to forget that each finger is made up of four bones, not three, and that the thumb is made up of three bones, not two. The bones that form the solid structure for what we call the palm of the hand are actually parts of the fingers.

Here is the same drawing of the hand and wrist that I posted in Wrist 
Palm up view of right hand
Circles, Part Two (May, 2013). Look at it now for the bones that meet the wrist bones on one end and help form the main knuckle joints on the other end. These bones are called metacarpal bones, and they are located in the palm of the hand. Notice how they fit rather snugly at the wrist, but they glide with the finger bones, called phalanges, at the knuckles. This arrangement allows for a lot of movement at these joints, called the metacarpal/phalangeal joints, or MCP for short.

The MCP joints allow fingers to move up and down as well as side to side. However, there is no circular movement available at these joints. Just as our brains attempt to see circles at the wrist, our brains may attempt to see circles at the MCP joints. If you gently move your index finger in differently directions, you will notice that you cannot describe a circle at this joint.  Piano action does not respond to circular movement, as we discovered when looking at an action model in Now, Weight!, Part Three. It requires that the key be sent down, not around. It is possible to trace a circle with the fingertip, but adding even the small amount of force required to send down a piano key makes this a challenging movement. Therefore I will eliminate the theory of finger circles from the list of possible ways to change sound at the piano.

The next post will explore what tissues move finger bones.

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