This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Spinal Injury, Subject name: Orthopaedics
A 10-year-old boy on examination was found to have scoliosis and tuft of hairs over skin of lumbar spine. He has weakness and features of lower motor neuron paralysis in both lower limbs. X-ray spine reveals the 2 lumbar veebrae at that level are fused. Most likely diagnosis is 
Select and explain. 
A. Hemiveebra, B. Diastematomyelia, C. Sacrococcygeal teratoma, D. Spinomuscular Dystrophy
B: Diastematomyelia
Answer: B: Diastematomyelia 
Explanation: Diastematomyelia (split cord malformation), refers to a type of spinal dysraphism (spina bifida occulta) when there is a longitudinal split in the spinal cord. Diastematomyelia signs and symptoms of tethered cord, although patients with mild type II may be minimally affected or entirely asymptomatic. Presenting symptoms include: leg weakness, low back pain, scoliosis, incontinence Associated anomalies including: meningocoele, neurenteric cyst, dermoid, clubfoot, spinal cord lipoma, haemangioma overlying spine. Type I: duplicated dural sac, with common midline spur (osseous or fibrous) and usually symptomatic Type II: single dural sac containing both hemicords; impairment less marked.