It's called a Stokes stretcher, they are still used frequently in the Navy. The casualty doesn't fall out when going up and down ladders on a ship. It also has a secondary function, if you have a patient (drunk) that requires restraint you tie two of them together and that's called getting 'clamshelled'. It doesn't matter how much fight you have, you aren't going anywhere and you are in a nice convenient carry on bag.
pa
Location: Pennhurst State School Gallery: Forgotten