The sphenoid bone carries its share of creating part of the base of the cranium. While it can be seen laterally and inferiorly, the shape of the bone is a bit unusual and is often described as moth or butterfly like. The butterfly shape looks very much like the body accompanied by the two wings which form the orbit. The “body” of the bone consists of the sphenoidal sinuses and the saddle shaped depression which is remarkably prominent. This is called the sella turcica. Commonly referred to as “Turk’s saddle,” this is where the pituitary gland resides. The lateral walls of the nasal cavity are assisted in formation by the inferior projection of pterygoid process. The sphenoid bone is associated with ample foramina properties.
The smaller portion of the “wing” in the rear of the skull helps create a large opening that allows the transfer of optic nerve passageway through the optic canal. The ophthalmic artery also transverses through this passageway. A triangular opening that can be found in between the “wings” associated with the sphenoid bone. This opening is known as the superior orbital fissure and is designed to allow the ophthalmic nerve safe passage to the eyes. The ophthalmic nerve is part of the trigeminal nerve. Additionally, the trochlear nerve, the oculomotor nerve, and the abducens nerve all travel through this same triangular opening.
The mandible nerve passes through an opening known as the foramen ovale. This small opening rests at the base of the lateral pterygoid plate. The rear angle of the sphenoid bone contains a small opening known as the foramen spinosum which allows the middle miningeal nerves to pass through the sphenoid bone. Between the sphenoid bone and the and the petrous part of the temporal bone, the foramen lacerum opens to allow the internal carotid artery as well as part of the ascending pharyngeal artery known as the meningeal branch to pass. The maxillary nerve makes its passage through the foramen known as the rotundum which is located just behind the superior orbital fissure.
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