The hand muscles that are made strong are palm and thumb. Fingers have no muscle in them. they are skin, fat,ligature and bone. There is no muscle to make fingers stronger. Grip is made stronger through the hand muscles.
repetition and compression can condition the practitioner to not be affected so readily by the neuralgia associated with bashing your fingers onto something, having them bent etc.
gripping exercises strengthen the palm and thumb muscle.
illustration:
http://l.yimg.com/a/i/edu/ref/ga/s/427.jpg