Base of skull

The base of skull, also known as the cranial base or the cranial floor, is the most inferior area of the skull. It is composed of the endocranium and the lower parts of the skull roof.

Skull base
Base of the skull, inner surface
Base of the skull, inferior or outer surface. Showing various muscle attachments.
Details
Identifiers
Latin	basis cranii externa et. interna
MeSH	D019291
TA	A02.1.00.044
FMA	52801
Anatomical terms of bone

Contents

Structure

Base of the skull. Inferior surface, attachment of muscles marked in red.

Structures found at the base of the skull are for example:

Bones

There are five bones that make up the base of the skull:

• Ethmoid bone
• Sphenoid bone
• Occipital bone
• Frontal bone
• Temporal bone

Exobasis

Sinuses

• Occipital sinus
• Superior sagittal sinus
• Superior petrosal sinus

Foramina of the skull

• Foramen cecum
• Optic foramen
• Foramen lacerum
• Foramen rotundum
• Foramen magnum
• Foramen ovale
• Jugular foramen
• Internal auditory meatus
• Mastoid foramen
• Sphenoidal emissary foramen
• Foramen spinosum

Endobasis-resistances beams

Endobasis-resistances nodes

Sutures

• Frontoethmoidal suture
• Sphenofrontal suture
• Sphenopetrosal suture
• Sphenoethmoidal suture
• Petrosquamous suture
• Sphenosquamosal suture

Other

The foramina in the base of the skull are exit and entry-points for veins, arteries and cranial nerves.

The cranial nerves as they exit through various foramina.

• Sphenoidal lingula
• Subarcuate fossa
• Dorsum sellae
• Jugular process
• Petro-occipital fissure
• Condylar canal
• Jugular tubercle
• Tuberculum sellae
• Carotid groove
• Fossa hypophyseos
• Posterior clinoid processes
• Sigmoid sulcus
• Internal occipital protuberance
• Internal occipital crest
• Ethmoidal spine
• Vestibular aqueduct
• Chiasmatic groove
• Middle clinoid process
• Groove for sigmoid sinus
• Trigeminal ganglion
• Middle cranial fossa
• Anterior cranial fossa
• Middle meningeal artery
• Cribriform plate
• Posterior cranial fossa
• Nasociliary nerve
• Hypoglossal canal

Additional images

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  Base of the skull. Upper surface

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  Base of skull

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  Base of skull - crista galli, cribriform plate and foramen cecum

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  Base of skull - sella turcica

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  The anterior, middle and posterior cranial fossa in different colors