Which congenital defect involves failure of the spinal canal to close around the spinal cord and typically occurs in the first month?

Which congenital defect involves failure of the spinal canal to close around the spinal cord and typically occurs in the first month?

• A. Spina Bifida
• B. Cleft Lip
• C. Anencephaly
• D. Hydrocephalus

Answer: (A)

The key idea is neurulation—the process in early development where the neural tube forms to become the brain and spinal cord, and the spine must close around this tube. When the posterior part of the neural tube fails to fuse properly, the bones of the spine don’t encase the spinal cord, leading to spina bifida. This happens very early in pregnancy, typically within the first month, as the neural tube is closing. Depending on severity, the opening can be minor or more involved with the spinal cord or meninges protruding. Other conditions listed are different developmental problems: cleft lip is a facial fusion issue occurring weeks earlier; anencephaly results from failure of the cranial neural tube to close, causing missing brain and skull; hydrocephalus is an accumulation of cerebrospinal fluid that can arise from various causes but isn’t itself a failure of spinal canal closure.

The key idea is neurulation—the process in early development where the neural tube forms to become the brain and spinal cord, and the spine must close around this tube. When the posterior part of the neural tube fails to fuse properly, the bones of the spine don’t encase the spinal cord, leading to spina bifida. This happens very early in pregnancy, typically within the first month, as the neural tube is closing. Depending on severity, the opening can be minor or more involved with the spinal cord or meninges protruding. Other conditions listed are different developmental problems: cleft lip is a facial fusion issue occurring weeks earlier; anencephaly results from failure of the cranial neural tube to close, causing missing brain and skull; hydrocephalus is an accumulation of cerebrospinal fluid that can arise from various causes but isn’t itself a failure of spinal canal closure.