The lesser wings of the sphenoid or orbito-sphenoids are two thin triangular plates, which arise from the upper and anterior parts of the body, and, projecting lateralward, end in sharp points [Fig.

The main features of the lesser wing are the optic canal, the anterior clinoid process, and the superior orbital fissure.

This fissure is of a triangular form, and leads from the cavity of the cranium into that of the orbit: it is bounded medially by the body; above, by the small wing; below, by the medial margin of the orbital surface of the great wing; and is completed laterally by the frontal bone.

The posterior border, smooth and rounded, is received into the lateral fissure of the brain; the medial end of this border forms the anterior clinoid process, which gives attachment to the tentorium cerebelli; it is sometimes joined to the middle clinoid process by a spicule of bone, and when this occurs the termination of the groove for the internal carotid artery is converted into a foramen (carotico-clinoid).

This article incorporates text in the public domain from page 151 of the 20th edition of Gray's Anatomy (1918)