An infant is born with a wide-based, shuffling gait at 18 months, a prominent midline scalp mass that transilluminates, and a Chiari I malformation on MRI. The scalp mass is a meningocele through which structure?

• A Foramen magnum
• B Posterior fontanelle
• C Coronal suture dehiscence
• D A midline defect in the skull (cranium bifidum), most commonly in the occipital region ✓

Explanation

Cranial meningocele is a herniation of the meninges (and CSF) through a defect in the skull vault (cranium bifidum) without brain tissue herniation; it transilluminates brightly. The occipital region is the most common site for posterior cranial meningocele. When brain parenchyma herniates with the meninges it becomes an encephalocele, which would not transilluminate fully. These defects result from failure of the neural tube to close, analogous to spina bifida in the spine.

Reference: BD Chaurasia's Human Anatomy, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.