Anatomical Characteristics Of The Lesser Wing Of The Sphenoid

Description

Lesser wings (alae minores) of the sphenoid project laterally from the body of the sphenoid at the skull base, forming sharp, shelf-like plates that contribute to the posterior margin of the anterior cranial fossa and the roof of the orbit. Medially, each lesser wing roots into the sphenoid body near the jugum sphenoidale and the prechiasmatic (chiasmatic) sulcus, while its posterior border creates the superior boundary of the superior orbital fissure. Near the medial end, the optic canal traverses the base of the wing and adjacent sphenoid body, transmitting the optic nerve (CN II) and ophthalmic artery; the anterior clinoid process extends posteriorly from the medial tip as a key landmark at the parasellar region. Edges are crisp. Bony relationships are unambiguous. Clinical relevance centers on the optic canal and anterior clinoid process, where small differences in bony contour can influence exposure of the supraclinoid internal carotid artery and optic nerve during skull base and aneurysm surgery. Compression or invasion of the optic canal by sphenoid wing meningioma can present with progressive unilateral visual loss, and fractures involving the lesser wing may narrow the canal or disrupt the optic strut at the junction with the sphenoid body. The fixed perspective emphasizes the canal’s osseous boundaries and the lesser wing’s posterior edge as the dividing line between the anterior cranial fossa superiorly and the orbital apex and superior orbital fissure inferiorly, a relationship learners often struggle to visualize from flat diagrams. Use this illustration in head and neck anatomy, neuroanatomy, or radiology teaching to orient CT bone windows of the sphenoid and to label the optic canal, superior orbital fissure, and anterior clinoid process with Terminologia Anatomica terms. It also suits operative atlases discussing anterior clinoidectomy, optic nerve decompression, and parasellar approaches where millimeters of bone matter. Anatomical accuracy verified by SciePro's Medical Advisory Board.