Final answer:
Lowering the legs slowly from the lithotomy to the supine position during general anesthesia is done to prevent hypotension.
Step-by-step explanation:
The purpose of lowering the legs slowly from the lithotomy to the supine position during general anesthesia is to prevent hypotension. When a patient is under general anesthesia, there is a risk of a sudden drop in blood pressure. Lowering the legs slowly allows for a gradual redistribution of blood flow and helps prevent hypotension.