Fracture and dislocation.

A fracture is a linear deformation or discontinuity of a bone produced by the application of a force that exceeds the modulus of elasticity (ability to bend) of a bone. Normal bones require excessive force to fracture. Disease, tumor-related diseases, or tumors themselves weaken the physical structure of bones, which reduces their ability to withstand an impact. Bones respond to stresses placed upon them and can thus be strengthened through physical conditioning and made more resistant to fracture. This is a normal part of training in many athletic activities.