RSI elbow injury. Coloured X-ray of a human elbow joint suffering arthrosis deformans due to a repetitive strain injury (RSI). This is the elbow of a construction worker whose work with pneumatic tools caused shocks to the elbow. At upper left is the partly deformed humerus bone with its rounded end forming part of the elbow joint. At lower centre and centre right are bones of the forearm. The space between the joint (orange) reveals that the normally smooth articulating surfaces of these bones has become jagged; cartilage and bone damage has occurred. This leads to pain and stiffness. RSI can affect construction and assembly-line workers and typists whose joints are overused.