What are the three cranial fossae and what do they support?

The floor of the cranial cavity is divided into three descending fossae: the anterior cranial fossa (highest, supports frontal lobes), middle cranial fossa (intermediate, supports temporal lobes), and posterior cranial fossa (lowest, houses cerebellum, pons, and medulla).

What structures pass through the cribriform plate in the anterior cranial fossa?

The cribriform plate transmits olfactory nerve filaments from the nasal mucosa to the olfactory bulbs, as well as anterior and posterior ethmoidal nerves and vessels.

Which foramina are found in the middle cranial fossa and what do they transmit?

Key foramina in the middle cranial fossa include the optic canal (transmits optic nerve and ophthalmic artery), superior orbital fissure (transmits cranial nerves III, IV, V1, VI, and ophthalmic veins), foramen ovale (transmits mandibular nerve, accessory meningeal artery, lesser petrosal nerve, and an emissary vein), and foramen spinosum (transmits middle meningeal artery and meningeal branch of V3).

What is the clinical significance of fractures in the middle cranial fossa?

Fractures in the middle cranial fossa are the most common cranial base fractures and can lead to complications such as CSF otorrhea (if the tegmen tympani is torn) and damage to nerves like the facial and vestibulocochlear nerves.

What structures pass through the foramen magnum in the posterior cranial fossa?

The foramen magnum transmits the medulla, spinal roots of cranial nerve XI, vertebral arteries, spinal arteries, meninges, and a sympathetic plexus.

What is the risk associated with raised intracranial pressure in the posterior cranial fossa?

Raised intracranial pressure in the posterior cranial fossa can cause cerebellar tonsil herniation through the foramen magnum, a serious condition that may compress vital brainstem structures.

Which bones form the anterior cranial fossa?

The anterior cranial fossa is formed by parts of the frontal, ethmoid, and sphenoid bones.

Cranial Base – Anterior, Middle & Posterior Fossae

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