Finger Anatomy

[nia_kurniati]

I have a student 12 years old and his finger always touch the key like letter L.  Not just flat but L. His finger is skinny. I always remind him to shape it like grabbing a ball. He already study for about 3 years but less less practice.
Do you think he can change or not? How?
Hope you understand what I mean. Thanks.

[jgallag]

Which joints are bending and, if any, which joints are inverting/locking? I don't understand what you mean by "L". Each finger has three joints, which I refer to as the knuckle joint (which joins the finger to the hand), the mid-joint, and the nail joint. Please give a more specific description, a picture would be especially nice.

And, yes, I do think he could change, but I'd need more info.