Encephalocele is a herniation of a portion of the brain and/or meninges through a defect of the bony skull table. The condition may be congenital or result from trauma or surgery.

In the United States the incidence is 1 to 4:10,000 live births; internationally there is no estimate available. Females are affected more often than males.

Congenital encephalocele is produced by a defect in the closure of the embryonic neural tube. The closure defect results in an abnormality of the skull and meninges. Encephalocele may also occur as the result of failed basilar ossification. This defect can potentially occur at several skull locations.