Final answer:
The subject of this question is medicine, specifically the surgical procedure of lithotomy. The student is asking about the proper positioning of the patient during the procedure.
Step-by-step explanation:
The subject of this question is medicine. The word 'lithotomy' refers to a surgical procedure used to remove a calculus (stone) from the urinary tract. When the question mentions that it should be placed at an even height, it is likely referring to the positioning of the patient during the procedure. In lithotomy position, the patient lies on their back with their legs raised and supported in stirrups, allowing access to the perineum. In order to perform the procedure successfully and safely, it is important to ensure that the patient is positioned at a comfortable and even height for the surgeon.