A skull defect resulting in exposure or extrusion of the brain is known as which condition?

A skull defect resulting in exposure or extrusion of the brain is known as which condition?

• A. Exencephaly
• B. Anencephaly
• C. Encephalocele
• D. Microcephaly

Answer: (A)

Exencephaly is a skull defect in which the calvarium (skull bones) fails to form, leaving brain tissue exposed outside the head. This results from incomplete closure of the cranial portion of the neural tube, so the brain is not covered by bone or skin. It is different from anencephaly, where brain tissue is largely absent along with the skull; from encephalocele, where brain and meninges protrude through a skull defect but are usually contained in a sac; and from microcephaly, where the head and brain are abnormally small but the skull remains intact.

Exencephaly is a skull defect in which the calvarium (skull bones) fails to form, leaving brain tissue exposed outside the head. This results from incomplete closure of the cranial portion of the neural tube, so the brain is not covered by bone or skin. It is different from anencephaly, where brain tissue is largely absent along with the skull; from encephalocele, where brain and meninges protrude through a skull defect but are usually contained in a sac; and from microcephaly, where the head and brain are abnormally small but the skull remains intact.