Final answer:
The best place for a lift sheet under a patient is underneath their body, from the shoulders to the buttocks, running parallel to the length of the patient's body.
Step-by-step explanation:
When lifting and moving a patient up in bed, the best place for a lift sheet is underneath the patient's body.
The lift sheet should be positioned from the patient's shoulders to their buttocks, running parallel to the length of the patient's body.