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Internal Features of Base of Skull:

Divided into anterior, middle, and posterior cranial fossae

Anterior cranial fossa

Contains frontal lobe of brain
Formed by frontal bone anteriorly, ethmoid bone medially, and lesser wing of sphenoid bone posteriorly

Features

Frontal crest—midline bony extension of frontal bone
Foramen cecum—foramen at base of frontal crest
Crista galli—midline ridge of bone from ethmoid posterior to foramen cecum
Cribriform plate—thin, sievelike plate of bone on either side of crista galli, which transmits olfactory

Contains temporal lobe, hypothalamus, and pituitary gland
Formed by greater wing and body of sphenoidal bone, petrous temporal bone, lesser wing of sphenoidal bone

Sella turcica—central depression in the body of the sphenoid bone for pituitary gland
Tuberculum sellae—swelling anterior to sella turcica
Dorsum sellae—crest on the body of the sphenoid bone posterior to sella turcica
Anterior clinoid processes—medial projections of lesser wings of sphenoidal bones
Posterior clinoid processes—swelling at either end of dorsum sellae
Foramen lacerum (one on each side)—jagged opening closed by plate of cartilage in life, transmits nothing

Contains four foramina in a crescent on either side in the body of the sphenoidal bone

Contains cerebellum, pons, and medulla oblongata
Composed largely of occipital bone, body of sphenoidal bone, petrous, and mastoid parts of temporal bone

Foramen magnum—transmits spinal cord
Internal occipital crest—divides posterior fossa into two lateral cerebellar fossae
Grooves for transverse and sigmoid dural venous sinuses
Jugular foramen—transmits sigmoid sinus (internal jugular vein) and several cranial nerves
Internal acoustic meatus—anterior and superior to jugular foramen, transmits facial and vestibulocochlear nerves (CN VII and CN VIII)
Hypoglossal canal—anterolateral and superior to foramen magnum, transmits the hypoglossal nerve (CN XII)