This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Abdomen and pelvis, Subject name: Anatomy
Boundaries of ischiorectal fossa are 
Select and explain. 
A. Posterior : Perineal membrane, B. Anterior : Sacrotuberous ligament, C. Lateral : Obturator internus, D. Medial : Gluteus maximus
C: Lateral : Obturator internus
Answer: C: Lateral : Obturator internus 
Explanation: The boundaries of ischiorectal fossa: floor: deep transverse perineal fascia. medial wall: external anal sphincters/anal canal; levator ani muscle. lateral wall: ischial tuberosity; obturator internus muscle; obturator fascia. apex: intersection of levator ani and obturator internus muscle ref - BDC vol2 pg415, researchgate.net