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
[{'content': 'Boundaries of ischiorectal fossa are \nSelect and explain. \nA. Posterior : Perineal membrane, B. Anterior : Sacrotuberous ligament, C. Lateral : Obturator internus, D. Medial : Gluteus maximus', 'role': 'user'}, {'content': 'Answer: C \nExplanation: 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', 'role': 'assistant'}]