Abstract: A leg positioning assembly includes a pillow adapted to separate the knees of a patient and to maintain the knees in flexion. The pillow is preferably substantially three-lobed, with two lobes forming a base portion and a third lobe forming a portion which separates the knees of the patient. A raised portion on each of the lobes forming the base portion can be provided to support and flex the legs at the knees. Fastening structure can be provided to secure the pillow to a patient support. Other fastening structure can be provided to secure the pillow to the legs of the patient.