Middle cranial fossa
The butterfly-shaped middle cranial fossa lies deeper within the internal cranial base in its center, and it is wider than the anterior cranial fossa.
This fossa in its central part houses the pituitary gland and temporal lobes of the brain on the sides of it.
It is formed by the following structures:
- Body and greater wings of the sphenoid
- Squamous part of the temporal bone
- Anterior surface of the petrous part of the temporal bone
The borders of the middle cranial fossa are defined by:
- Anteriorly - posterior margin of the lesser wings, prechiasmatic sulcus, and part of the body of the sphenoid bone;
- Posteriorly - superior margins and anterior surface of the petrous part of the temporal bone, and the dorsum sellae of the sphenoid bone;
- Laterally - squamous parts of the temporal bones, parietal bones, and the greater wings of the sphenoid bone.
The middle cranial fossa has several openings:
- Optic canal - connects the orbit with the middle cranial fossa; transmits the optic nerve (CN II) and ophthalmic artery;
- Superior orbital fissure - connects the orbit with the middle cranial fossa; transmits the oculomotor (CN III), trochlear (CN IV), ophthalmic (CN V1), and abducens (CN VI) nerves, ophthalmic veins, and sympathetic nerve fibers;
- Foramen rotundum - connects the pterygopalatine fossa with the middle cranial fossa; transmits maxillary nerve (CN V2);
- Foramen ovale - connects the infratemporal fossa with the middle cranial fossa; transmits the mandibular nerve (CN V3), accessory meningeal artery, lesser petrosal nerve, and an emissary vein;
- Foramen spinosum - connects the infratemporal fossa with the middle cranial fossa; transmits the middle meningeal artery and vein, and meningeal branch of the mandibular nerve (CN V3);
- Internal opening of the carotid canal - connects the carotid canal and external cranial base (external opening of the carotid canal is located on the external cranial base) with the middle cranial fossa; transmits internal carotid artery, internal carotid venous plexus, carotid plexus of nerves;
- Foramen lacerum - connects the external cranial base with the middle cranial fossa; transmits artery and nerve of the pterygoid canal, meningeal branch of the ascending pharyngeal artery, emissary veins;
- Hiatus and groove for greater petrosal nerve - connects the facial canal with the middle cranial fossa; transmits the greater superficial petrosal nerve and petrosal branch of the middle meningeal artery;
- Hiatus and groove for lesser petrosal nerve - connects the tympanic cavity with the fossa; transmits the lesser petrosal nerve.