In 2011, 1.6 million hospital discharges and 14.7 million emergency department visits were made by people aged 18 years and older for treatment of a musculoskeletal injury. Another 35.5 million musculoskeletal injuries were serious enough to receive outpatient treatment. The most frequent type of injury involving hospitalization was a fracture, with people aged 85 years and older accounting for 45% of hospitalizations for fractures. Injuries seen in emergency departments were distributed across all types of musculoskeletal injuries (fractures, dislocations, sprains and strains, contusions, open wounds, and other types of musculoskeletal injuries). The youngest and oldest age groups (18 to 44 years and 85 years and older) had the highest rate of injury seen in the ED (6.9/100 persons and 9.9/100, respectively). Because of  the large size of the 18- to 44-year age group (48% of the US population is over age 18), this group constituted a majority of all injury cases seen, with the exception of fractures. (Reference Table 9B.6.2 PDF CSV and Table 6A.2.2.2 PDF CSV)