5 Cranial Skull Base

5

Cranial Skull Base

Shawneen M. Gonzalez


Introduction
This chapter will cover basic anatomy of the cranial skull base along with common radiographic findings. The topics covered include developmental appearances and anatomical variants. Calcifications within the soft tissue of the brain are included in Chapter 6. Different portions of the cranial skull base will be seen on CBCT scans depending on the FOV used. Some of the radiographic findings covered in this chapter may not be visible on all scans and therefore should not be commented on by someone reviewing a scan.

Anatomy

This section will highlight anatomical landmarks of the cranial skull base and the bones they are a part of. Many of these landmarks are only identifiable when using a scan with a large field of view.

Axial

The axial figures (Figures 5.15.5) start from the superior aspect of the cranium moving inferiorly. The following anatomy is readily identifiable on axial views (Table 5.1).

Figure 5.1. Axial slice at the level superior to the orbits showing the frontal sinus (star).

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Figure 5.2. Axial slice at the level of the superior aspect of the orbits showing the crista galli (black arrow).

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Figure 5.3. Axial slice at the level of the midorbits showing the following sphenoid bone anatomy: the anterior clinoid process (A), sella turcica (S), and posterior clinoid process (P).

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Figure 5.4. Axial slice at the level of the inferior orbit/superior maxillary sinus showing the foramen lacerum (FL), carotid canal (CC), and petrous ridge (PR).

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Figure 5.5. Axial slice at the level of the midmaxilla showing the mastoid process with mastoid air cells (MAC), styloid process (SP), clivus/occipital bone (C), foramen magnum (FM), and pterygoid process (PP).

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Table 5.1. Anatomical landmarks identifiable on axial views with corresponding figures.

Bone Anatomical landmark Figures visible on
Frontal Frontal sinus 5.1
Ethmoid Crista galli 5.2
Sphenoid Anterior clinoid process
Sella turcica
Posterior clinoid process
Foramen lacerum
Pterygoid process
5.3
5.3
5.3
5.4
5.5
Temporal Carotid canal
Petrous ridge
Mastoid process
Styloid process
5.4
5.4
5.5
5.5
Occipital Clivus / occipital bone
Foramen magnum
5.5
5.5

Figure 5.6. Coronal slice at the anterior aspect of the nasal cavity showing the frontal sinus (star).

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Coronal

The coronal figures (Figures 5.65.11) start from the anterior aspect of the face moving posteriorly. The following anatomy is readily identifiable on coronal views (Table 5.2).

Figure 5.7. Coronal slice at the lateral aspect of the orbits showing the cribriform plate (white arrow) and crista galli (black arrow).

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Figure 5.8. Coronal slice at the aspect of the coronoid process showing the pterygoid process (PP), vidian canal (VC), foramen rotundum (FR), and anterior clinoid process (A).

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Figure 5.9. Coronal slice at the posterior aspect of the ramus showing the posterior clinoid process (P) and foramen lacerum (FL).

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Figure 5.10. Coronal slice at the aspect of the mastoid process showing the mastoid process with mastoid air cells (MAC) and depression of the sigmoid sinus (SS).

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Figure 5.11. Coronal slice at the posteriormost aspect showing the jugular foramen (JF) and petrous ridge (PR).

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Table 5.2. Anatomical landmarks identifiable on coronal views with corresponding figures.

Bone Anatomical landmark Figures visible on
Frontal Frontal sinus 5.6
Ethmoid Cribriform plate
Crista galli
5.7
5.7
Sphenoid Anterior clinoid process
Posterior clinoid process
Foramen lacerum
Foramen rotundum
Pterygoid process
Vidian canal
5.8
5.9
5.9
5.8
5.8
5.8
Temporal Petrous ridge
Mastoid process
Sigmoid sinus depression
5.11
5.10
5.10
Occipital Jugular foramen 5.11

Figure 5.12. Sagittal slice at the lateral aspect of the mastoid process showing the mastoid process with mastoid air cells (MAC) of the temporal bone is evident along with the external auditory meatus (EAM).

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Sagittal

The sagittal figures (Figures 5.125.15) start fro/>

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Jan 12, 2015 | Posted by in Oral and Maxillofacial Radiology | Comments Off on 5 Cranial Skull Base
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