Outdoor leaders and those involved in personal outdoor adventure pursuits must be knowledgeable in the assessment, treatment, and prevention of musculoskeletal injuries in the backcountry. In the wilderness medicine setting, extended time periods of patient care, rugged terrain, severe environmental conditions, and limited resources create emergency care situations that are considerably different from standard urban emergency response. In emergencies, the trip members are the first responders and are often the rescuers. This paper focuses on the assessment, treatment, and prevention of common injuries to the musculoskeletal system. Some basic information on bones and muscles is reviewed. When assessing an injury, the care provider must look at the mechanism of injury to determine the likelihood, type, and extent of injury. Stable musculoskeletal injuries include strains, caused by overstretching or tearing of muscles or tendons, and sprains, which involve stretches or tears of the ligaments. Stable injuries are treated with rest, ice, compression, and elevation (RICE) but generally do not require splinting. Unstable musculoskeletal injuries include fractures and dislocations and are treated with hands-on stabilization, traction in line, and splinting, in addition to RICE. The diagnosis, treatment, and potential need for evacuation are detailed for various types of injury within each category. The improvisation of splints from backcountry gear and their application to fracture or dislocation are discussed. (Author/SV)