The nervous system in utero

A mother who did not receive prenatal care gives birth to a stillborn baby with anencephaly. The distraught mother asks how this could have happened. In the development of the nervous system in utero, you recall that anencephaly is due to which of the following?
Dilatation of the ventricles caused by an excess of CSF
Failure of the anterior neuropore to close
Failure of the posterior neuropore to close
Failure of the bony vertebral arches to form properly in the sacrolumbar region
Failure of the bony skull to form properly in the occipital region

Correct answer
Failure of the anterior neuropore to close
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correct answer: B
Anencephaly occurs when the anterior neuropore fails to close during week 4 of gestation. It results in failure of the brain to develop, failure of the lamina terminalis to form, and failure of the bony cranial vault to form.
Dilatation of the ventricles caused by an excess of CSF (Choice A) leads to hydrocephalus, not anencephaly.

Failure of the posterior neuropore to close (Choice C) during week 4 of gestation results in lower neural tube defects such as spina bifida.

Failure of the bony vertebral arches to form properly in the sacrolumbar region (Choice D) results in spina bifida, not anenceaphly.

Failure of the bony skull to form properly in the occipital region (Choice E) results in encephalocele, characterized by the protrusion of the brian and meninges through the resulting openings.