Anatomy: Posterior Fossa, Hindbrain & Craniocervical Junction
Clivus
The clivus is a sloped bone at the base of the skull whose shape and angle are relevant to Chiari malformation and craniocervical measurements.
In short: Clivus
- It is a sloped bone at the base of the skull, in front of the brainstem.
- Its length and slope relate to posterior fossa size.
- It is used in craniometric measurements (such as the clivo-axial angle).
- A short or abnormally angled clivus can be associated with Chiari.
What it is
The clivus is a sloped portion of bone at the base of the skull, located in front of the brainstem and behind the nasal structures. Its shape, length, and angle are relevant to Chiari malformation and are used in measurements of the craniocervical junction.
Understanding Clivus
The clivus forms part of the floor of the posterior fossa and the front wall of the foramen magnum region. A shorter or more steeply angled clivus can contribute to a smaller posterior fossa, which is associated with Chiari I. The clivus is also used in craniometric measurements — for example, the clivo-axial angle (the angle between the clivus and the upper cervical spine), which helps assess for ventral brainstem compression and craniocervical alignment. Abnormalities such as platybasia (a flattened skull base) involve the clivus. Understanding the clivus helps clarify how skull-base anatomy relates to posterior fossa size and to the measurements used in evaluating Chiari and associated craniocervical conditions.
Why it matters
Understanding the clivus helps families see how skull-base bone shape relates to posterior fossa size and to the craniometric measurements (like the clivo-axial angle) used in evaluating Chiari and craniocervical alignment.
Common questions
What is the clivus?
A sloped bone at the base of the skull, in front of the brainstem.
How does it relate to Chiari?
Its shape relates to posterior fossa size and craniocervical measurements.
What measurement uses it?
The clivo-axial angle, among others.
Bottom line
The clivus is a sloped skull-base bone whose shape and angle relate to posterior fossa size and the craniometric measurements used in Chiari evaluation.
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