In the Soviet era, astronauts used a fully enclosed sleeping cabin to sleep, but after tests and experiments, it didn't do any good except occupying precious space, so they used a closed sleeping bag, just like the sleeping bag used on the ground, just hanging. Put your arms in your sleeping bag and tie your hands to your chest to avoid accidentally touching the switches of instruments and equipment.
During the space exploration, the United States experimented with various kinds of sleep, and finally adopted the same design to fix the sleeping bag, but the sleeping bag was designed differently, which limited the range of arm movement and did not need to be put in the sleeping bag.
China's space sleeping bag, like Russian space sleeping bag, enters the sleeping bag all over, including the arm, and is equipped with an eye mask.