Encephalocele/MeningoceleAn encephalocele is a region of herniated brain. The term meningocele refers to herniated dura (covering of the brain).
Etiology for Encephalocele/Meningocele
The brain and/or dura can herniate into the mastoid bone. There are four explanations for this anomaly. First, there may have been a congenital (present since birth) bony defect in the base of the skull when the cranial base was forming. With time and continued pulsations of the brain, the brain and/or dura can herniate through these openings. Secondly, a portion of the bone at the base of the brain may have been surgically removed during a previous operation. Again, with continued pulsations of the brain, these openings can enlarge, allowing herniation. Thirdly, severe head injury can lead to a loss of this bony partition. Lastly, a chronic middle ear and mastoid infection can also cause erosion of the bony partition.