This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Central Nervous System, Subject name: Pediatrics
[{'content': 'Myelomeningocele most commonly involves which region of spine: \nSelect and explain. \nA. Cervico-dorsal, B. Dorsolumbar, C. Lumbosacral, D. Sacro-coccygeal', 'role': 'user'}, {'content': "Answer: C \nExplanation: c. Lumbosacral(Ref: Nelson's 20/e p 2802-2803)Myelomeningocele involves lumbosacral region (75% of cases)Appearance: a sac-like cystic structure with remnants of neural tissue visible beneath the membrane, which occasionally ruptures and leaks CSF or an exposed flat neural placodeHydrocephalus with a type II Chiari malformation develops in 80% of patients with MMCThe lower the deformity in the neuraxis, the less likely is the risk of hydrocephalus.", 'role': 'assistant'}]