A fracture is a break in the bone or cartilage. It usually is a result of trauma but can be due to an acquired disease of bone such as osteoporosis or abnormal formation of bone in a congenital disease of bone such as osteogenesis imperfecta ("brittle bone disease").
Fractures are classified by their character and location. Examples of classification include "transverse fracture of the humerus," "spiral fracture of the femur," "greenstick fracture of the radius," "impacted fracture of the humerus," "linear fracture of the ulna," "oblique fracture of the metatarsal," "compression fracture of the vertebrae," and "depressed fracture of the skull."
Note that "comminuted fracture" in which the bone is fragmented is distinguished from a "compound (open) fracture."