Final answer:
Spina bifida is a birth defect of the spinal cord that occurs when the neural tube does not completely close during development. There are three classes of spina bifida: occulta, meningocele, and myelomeningocele.
Step-by-step explanation:
Spina bifida is a birth defect of the spinal cord that occurs when the neural tube does not completely close during development. There are three classes of spina bifida: occulta, meningocele, and myelomeningocele. Spina bifida occulta is the mildest form, where the vertebral bones do not fully surround the spinal cord but the spinal cord itself is not affected. Meningocele involves the protrusion of the meninges through the spinal column, while myelomeningocele involves both the protrusion of the meninges and the spinal nerves. Severe neurological symptoms can be present in myelomeningocele. Surgery is often necessary to close the opening or remove the cyst, and early surgery can help control further damage or infection.