I like the composition. Perhaps it is just my monitor, but the violin seems exceptionally dark. I keep trying to see the grain in the wood, which is distracting me from the violinist.
My wife plays violin, which might be why I seem to find the right hand to be the focus of the image, but it is out of focus. I really like the way the hand and the bow hair mimic the angles of the bridge. I think if I were photographing my wife playing I would try to include the scroll of the instrument, and probably the whole bow, but if you had done that here it would be a completely different composition.
Aside from the photo, it is interesting that she has two fine tuners on her instrument; typically there is only one.