In spina bifida with myelomeningocele, which anatomical abnormality occurs?

• A. The brain is fully intact.
• B. There is no risk of infection.
• C. The limbs are always normal.
• D. Cerebrospinal fluid and spinal nerves exit the vertebral column.

Answer: (D)

In myelomeningocele, the spinal column fails to close properly, and the spinal cord plus meninges herniate through the vertebral defect, forming a sac that communicates with the outside. This means cerebrospinal fluid and nerve roots (spinal nerves) can extend beyond the vertebral column into the sac. The defect creates an opening that allows CSF and neural tissue to exit the normal confines of the spinal canal.

The statement about the brain being fully intact isn’t accurate, because there can be associated brain abnormalities with spina bifida, such as Chiari II malformation and hydrocephalus. Infection risk is real due to the exposed neural tissue, and great variability exists in limb function below the lesion—limbs are not always normal.