This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Lower limb, Subject name: Anatomy
Structure which passes through both greater and lesser sciatic foramen 
Select and explain. 
A. Nerve to quadratus femoris, B. Superior gluteal nerve, C. Nerve to obturator internus, D. Piriformis muscle
C: Nerve to obturator internus
Answer: C: Nerve to obturator internus 
Explanation: GREATER SCIATIC FORAMEN:- Gateway of gluteal region.1. pyriformis: key muscle of the region. 2. structures passing above pyriformis.A. Superior gluteal nerve B. Superior gluteal vessels. 3. Structures passing below the pyriformis:-Inferior gluteal nerve and vessels.Sciatic nerve Posterior cutaneous nerve of thighNerve to quadratus femorisNerve to obturator internus . Pudendal nerve. Internal pudendal vessels LESSER SCIATIC FORAMEN:-Gateway of the perineal region.1. Tendon of obturator internus2. Pudendal nerve 3. Internal pudendal vessels 4. Nerve to obturator internus. <img src=" /> {Reference: BDC 6E pg no.74}