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Medical Definition of Ala orbitalis
1. One of a bilateral pair of triangular, pointed plates extending laterally from the anterolateral body of the sphenoid bone. Forming the posteriormost portion of the floor of the anterior cranial fossa, their sharp posterior edge forms the sphenoidal ridge separating anterior and middle cranial fossae. The medial end of the lesser wing attaches to the body by means of two pedicles, thus forming the optic canal. The wing itself forms the superior margin of the supraorbital fissure. Synonym: ala minor ossis sphenoidalis, ala orbitalis, Ingrassia's apophysis, Ingrassia's wing. (05 Mar 2000)