A litter is a stretcher designed to be used where there are physical obstacles that impair movement, including other hazards such as, in confined spaces, on slopes or uneven terrain, or in densely forested areas.
They are most notably remembered from Korea and Vietnam images of United States Air Force Pararescue airmen or more recent Coast Guard video clips of helicopters rescuing injured people from isolated areas.
Litters used in mountain rescue usually are equipped with a cover or other material to protect the person from falling rocks.
[1] Originally designed by Charles F. Stokes,[2][3][4] these baskets have been notorious for spinning under the downdraft from the rotating helicopter blades.
[5] Design improvements have included using multiple attachment points, separate hold-down cables, and powered extension hoists to help save more lives.