Lesser Wing Of The Sphenoid, Anterior View

Description

Lesser wing of the sphenoid (ala minor) forms a sharp, triangular shelf at the anterosuperior aspect of the middle cranial fossa and contributes to the posterior roof of the orbit. From an anterior viewpoint, its thin plate is seen projecting laterally from the sphenoid body, with the medial root framing the optic canal as it passes toward the orbital apex. The anterior clinoid process appears as a medial posterior projection at the free edge, lying superior and slightly lateral to the sphenoid body, while the inferior margin relates to the superior orbital fissure region just below the wing’s posterior edge. Optic canal anatomy is unforgiving. In cranio-orbital approaches, the lesser wing and anterior clinoid define bony constraints around the optic nerve and ophthalmic artery, and their proximity explains why clinoidectomy and optic canal decompression require strict control of depth and direction to avoid iatrogenic injury. Anterior lighting and the isolated bony surface in this illustration make the free posterior border and the canal’s entrance easy to judge against the surrounding cranial base contours, which helps when correlating with CT bone windows or dry skull teaching specimens. Neurosurgery and ophthalmology texts can place this illustration alongside discussions of paraclinoid internal carotid artery aneurysms, optic nerve sheath meningioma extension, and the bony boundaries encountered in anterior cranial base and orbital apex exposure. Anatomy educators can also use it in head and neck, neuroanatomy, or radiologic anatomy courses to reinforce how the lesser wing separates the anterior cranial fossa (superior) from the orbital cavity (anterior and inferior) at the sphenoid-frontal junction. A small bone, big consequences. Anatomical accuracy verified by SciePro's Medical Advisory Board.