Upper extremity musculoskeletal disorders such as DeQuervain's tendonitis, carpal tunnel syndrome, and rotator cuff tendonitis have become increasingly common among working people in the United States. Extensive epidemiological investigation indicates that the adverse ergonomic exposures of force, repetition, vibration and certain postures are risk factors for development of many of these disorders. Assessment of patients with possible work-related upper limb disorders requires eliciting information about the illness, performing an examination about the illness, and obtaining information about adverse ergonomic exposures on and off from work. Treatment can only be successful when exposure to adverse ergonomic risk factors is reduced or eliminated.