If the posterior neuropore fails to close during development, what condition results?

If the posterior neuropore fails to close during development, what condition results?

• A. Anencephaly
• B. Spina bifida
• C. Encephalocele
• D. Myelomeningocele

Answer: (B)

During early development, the neural tube forms and closes at both ends. The posterior neuropore is the caudal end that must seal to create the spinal canal and vertebral arches. If this end fails to close, the spinal region doesn’t form properly, leading to spina bifida. In more severe cases, the meninges and sometimes the spinal cord protrude, which is a form of spina bifida known as myelomeningocele. The other conditions come from problems at the cranial end of neurulation: anencephaly results from failure of the cranial neuropore to close, and encephalocele involves herniation of brain tissue through skull defects. So the defect at the posterior neuropore specifically points to spina bifida.

During early development, the neural tube forms and closes at both ends. The posterior neuropore is the caudal end that must seal to create the spinal canal and vertebral arches. If this end fails to close, the spinal region doesn’t form properly, leading to spina bifida. In more severe cases, the meninges and sometimes the spinal cord protrude, which is a form of spina bifida known as myelomeningocele. The other conditions come from problems at the cranial end of neurulation: anencephaly results from failure of the cranial neuropore to close, and encephalocele involves herniation of brain tissue through skull defects. So the defect at the posterior neuropore specifically points to spina bifida.