Greater wing of sphenoid bone
The greater wing of the sphenoid bone, or alisphenoid, is a bony process of the sphenoid bone; there is one on each side, extending from the side of the body of the sphenoid and curving upward, laterally, and backward. Structure. The greater wings of the sphenoid are two strong processes of bone, which arise from the sides of the body, and are curved upward, laterally, and backward; the posterior part of each projects as a triangular process that fits into the angle between the squamous and the petrous part of the temporal bone and presents  at its apex a downward-directed process, the spine of sphenoid bone. Cerebral surface. The superior or cerebral surface of each greater wing [Fig. 1] forms part of the middle cranial fossa; it is deeply concave, and presents depressions for the convolutions of the temporal lobe of the brain. It has a number of foramina (holes) in it: Lateral surface. The lateral surface [Fig. 2] is convex, and divided by a transverse ridge, the infratemporal crest, into two portions. It is pierced by the foramen ovale and foramen spinosum, and at its posterior part is the sphenoidal spine, which is  frequently grooved on its medial surface for the chorda tympani nerve. To the sphenoidal spine are attached the sphenomandibular ligament and the tensor veli palatini muscle. Medial to the anterior extremity of the infratemporal crest is a triangular process that serves to increase the attachment of the lateral pterygoid muscle; extending downward and medialward from this process on to the front part of the lateral pterygoid plate is a ridge that forms the anterior limit of the infratemporal surface, and, in the articulated skull, the posterior boundary of the pterygomaxillary fissure. Orbital surface. The orbital surface of the great wing  [Fig. 2], smooth, and quadrilateral in shape, is directed forward and medially and forms the posterior part of the lateral wall of the orbit. Margin. Commencing from behind [Fig. 2], that portion of the circumference of the great wing that extends from the body to the spine is irregular. In front of the spine the circumference presents a concave, serrated edge, bevelled at the expense of the inner table below, and of the outer table above, for articulation with the squamous part of the temporal bone. At the tip of the great wing is a triangular portion, bevelled at the  expense of the internal surface, for articulation with the sphenoidal angle of the parietal bone; this region is named the pterion. Medial to this is a triangular, serrated surface, for articulation with the frontal bone; this surface is continuous medially with the sharp edge that forms the lower boundary of the superior orbital fissure, and laterally with the serrated margin for articulation with the zygomatic bone. Development. The greater wing of the sphenoid bone starts as a separate bone, and is still separate at birth in humans. Clinical significance. It causes the superior lateral nasal occipital nerve to malfunction. In  other animals. In many mammals, e.g. the dog, the greater wing of the sphenoid bone stays through life a separate bone called the alisphenoid.