Head's Law

When a painful stimulus is applied to a body part of low sensitivity (e.g., viscus) that is in close central connection with a point of higher sensitivity (e.g., soma), the pain is felt at the point of higher sensitivity rather than at the point where the stimulus was applied. 

Wolff's Law

Wolff's law states that every change in form and function of a bone, or in its function alone, is followed by certain definite changes in its internal architecture and equally definite secondary alteration in its mathematical laws (Morton's Medical Bibliography). A shorter version: Bone is deposited and resorbed in accordance with the stresses placed upon it.