Final answer:
The Lithotomy position is similar to the jackknife position as it also features the patient's hips flexed at a 90-degree angle, typically used in pelvic procedures.
Step-by-step explanation:
The position that is similar to the jackknife position, where the patient's hips are flexed at a 90-degree angle, is the Lithotomy position. This position is commonly used in medical procedures that involve pelvic examinations, gynecologic surgeries, or other procedures involving the genitals or rectum. In the Lithotomy position, the patient lies on their back with hips and knees flexed, and their feet are usually supported by stirrups, thus resembling the jackknife position which also involves significant hip flexion.