Skull & Cranial Anatomy

Skull base (cranial base)

The skull base is the bony floor of the skull on which the brain rests.

In short: Skull base (cranial base)

  • Basal encephaloceles protrude downward through the skull base.
  • It contains the sphenoid and ethmoid bones.
  • Skull-base encephaloceles may be hidden and approached endoscopically.
  • It separates the brain from the nose, sinuses, and throat.

What it is

It is the bottom of the cranium — the bony floor beneath the brain. It separates the brain above from the nose, sinuses, and throat below.

Understanding Skull base (cranial base)

Because the skull base separates the brain from the nose, sinuses, and throat, defects here let encephaloceles protrude internally rather than outward. These basal encephaloceles can be hidden and may present with nasal symptoms; they are frequently repaired through an endoscopic endonasal (through-the-nose) approach. The skull base contains the sphenoid and ethmoid bones and important structures like the cribriform plate and sella turcica.

Why it matters

Understanding the skull base explains why some encephaloceles are hidden, why nasal masses must be imaged before any biopsy, and why endoscopic repair through the nose is possible for these types.

Common questions

What protrudes through the skull base?

Basal encephaloceles.

Are they visible?

Often not — they protrude internally.

How are they repaired?

Often endoscopically through the nose.

Bottom line

The skull base is the floor of the cranium, where hidden basal encephaloceles protrude internally.

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