Spina bifida is defined as which birth defect?

• A. Birth defect in which the child is born without spinal vertebrae.
• B. Congenital inflammation of the spinal cord, usually in the neck.
• C. Chronic pressure on the brain caused by excess cerebrospinal fluid.
• D. Birth defect caused by incomplete closure of the spinal column.

Answer: (D)

Spina bifida is a birth defect caused by incomplete closure of the spinal column. During early embryonic development, the bones forming the spine should fuse to form a complete spinal canal; when this process fails, there’s a gap in the vertebral arches. In milder forms the gap is covered by skin, while in more severe forms the meninges or even the spinal cord can protrude through the opening. This contrasts with conditions like spinal cord inflammation or hydrocephalus from excess cerebrospinal fluid. Understanding this opening of the spinal column also explains why folic acid before and during early pregnancy lowers risk and why prenatal screening can detect spina bifida.