The purpose of this commentary is to present recent epidemiological findings regarding work-related musculoskeletal disorders (WMSDs) of the hand and wrist, and to summarize experimental evidence of underlying tissue pathophysiology and sensorimotor changes in WMSDs. Sixty-five percent of the 333 800 newly reported cases of occupational illness in 2001 were attributed to repeated trauma. WMSDs of the hand and wrist are associated with the longest absences from work and are, therefore, associated with greater lost productivity and wages than those of other anatomical regions. Selected epidemiological studies of hand/wrist WMSDs published since 1998 are reviewed and summarized. Results from selected animal studies concerning underlying tissue pathophysiology in response to repetitive movement or tissue loading are reviewed and summarized. To the extent possible, corroborating evidence in human studies for various tissue pathomechanisms suggested in animal models is presented. Repetitive, hand-intensive movements, alone or in combination with other physical, nonphysical, and nonoccupational risk factors, contribute to the development of hand/wrist WMSDs. Possible pathophysiological mechanisms of tissue injury include inflammation followed by repair and/or fibrotic scarring, peripheral nerve injury, and central nervous system reorganization. Clinicians should consider all of these pathomechanisms when examining and treating patients with hand/wrist WMSDs. Keywordscarpal tunnel syndrome; hand/wrist tendinitis; inflammation; neuroplasticity; repetitive-motion injuryThe US Department of Labor 20 defines work-related musculoskeletal disorders (WMSDs) as injuries or disorders of the muscles, nerves, tendons, joints, cartilage, and spinal discs associated with exposure to risk factors in the workplace. WMSDs do not include disorders caused by slips, trips, falls, motor vehicle accidents, or similar accidents. 20 Sixty-five percent of the 333 800 newly reported cases of occupational illness in 2001 were attributed to repeated trauma. 21 WMSDs account for approximately one third of all lost workday illnesses. 20Address correspondence to Dr Ann E. Barr, Physical Therapy Department, College of Health Professions, Temple University, 3307 North Broad Street, Philadelphia, PA 19140. E-mail: aebarr@temple.edu. Sources of grant support: National Institute of Arthritis and Musculoskeletal and Skin Diseases, Grant # AR46426 (to AEB); Foundation for Physical Therapy, New Investigator Fellowship Training Initiative Award (to AEB); National Institute of Occupational Safety and Health, Grant # OH03970 (to MFB). Detailed summaries of the studies reviewed by NIOSH and the NRC will not be repeated here. The interested reader is encouraged to consult these documents and their extensive bibliographies. NIH Public AccessBoth the NIOSH and NRC reviews identified gaps in the literature with the hope of guiding future research. In recent years, investigators have begun to address some of these issues. For this commentary, only epidemiolo...