Orthopedic surgery or orthopedics (also spelled orthopaedic surgery and orthopaedics) is the branch of surgery concerned with conditions involving the musculoskeletal system. Orthopedic surgeons use both surgical and nonsurgical means to treat musculoskeletal trauma, sports injuries, degenerative diseases, infections, tumors, and congenital disorders.
Nicholas Andry coined the word "orthopaedics" in French as orthopédie, derived from the Greek words orthos ("correct", "straight") and paidion ("child"), when he published Orthopedie (translated as Orthopaedia: or the Art of Correcting and Preventing Deformities in Children) in 1741. The correction of spinal and bony deformities became the cornerstone of orthopedic practice.
Aviation safety is a term encompassing the theory, investigation, and categorization of flight failures, and the prevention of such failures through regulation, education, and training. It can also be applied in the context of campaigns that inform the public as to the safety of air travel.
To assume a brace or crash position is an instruction that can be given to prepare for a crash, such as on an aircraft; the instruction to brace for impact is often given if the aircraft must make an emergency landing over land or water.