Neural tube defects occur due to interference with cranial or caudal closure during embryological development between 3-4 weeks. Risk factors include genetic and environmental influences. Neural tube defects are classified as open spina bifida, where the spinal cord and meninges are exposed through an opening in the vertebral column, or occult spina bifida, where defects are hidden below the skin surface and can include tethered cord, dermal sinus, lipoma of the cord, diastematomyelia, or thickened filum terminal. Clinical features of neural tube defects include weakness, sphincter disturbances, back pain, scoliosis, sensory deficits, and cutaneous signs.