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 The body of the sphenoid bone, more or less cubical in shape, is hollowed out in its interior to form two large cavities, the sphenoidal sinuses, which are separated from each other by a septum. Superior surface The superior surface of the body ...

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 The temporal bones are situated at the sides and base of the skull, and lateral to the temporal lobes of the cerebral cortex. The temporal bones are overlaid by the sides of the head known as the temples, and house the structures of the ears ...

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

ig. 1 IG, Ig, or ig may refer to: Companies * IG Farben, a former German industrial conglomerate * IG Group, a UK financial services company * IG Recordings, a record label formed by the Indigo Girls, an American folk/rock duo * Production I.G, a Japan ...

forms part of the middle cranial fossa; it is deeply concave, and presents depressions for the convolutions of the

temporal lobe The temporal lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The temporal lobe is located beneath the lateral fissure on both cerebral hemispheres of the mammalian brain. The temporal lobe is involved in proc ...

of the brain. It has a number of foramina (holes) in it: * The foramen rotundum is a circular aperture at its anterior and medial part; it transmits the maxillary nerve. * The

foramen ovale There are multiple structures in the human body with the name foramen ovale (plural: ''foramina ovalia''; Latin for "oval hole"): * Foramen ovale (heart), in the fetal heart, a shunt from the right atrium to left atrium * Foramen ovale (skull), at ...

is behind and lateral to this; it transmits the

mandibular nerve In neuroanatomy, the mandibular nerve (V) is the largest of the three divisions of the trigeminal nerve, the fifth cranial nerve (CN V). Unlike the other divisions of the trigeminal nerve ( ophthalmic nerve, maxillary nerve) which contain only ...

, the accessory meningeal artery, and sometimes the lesser petrosal nerve. * The

sphenoidal emissary foramen In the base of the skull, in the great wings of the sphenoid bone, medial to the foramen ovale, a small aperture, the sphenoidal emissary foramen, may occasionally be seen (it is often absent) opposite the root of the pterygoid process. When pre ...

is occasionally present; it is a small aperture medial to the foramen ovale, opposite the root of the pterygoid process; it opens below near the

scaphoid fossa In the pterygoid processes of the sphenoid, above the pterygoid fossa is a small, oval, shallow depression, the scaphoid fossa, which gives origin to the Tensor veli palatini. It is not the same as and has to be distinguished from the scaphoid ...

, and transmits a small vein from the cavernous sinus. * The foramen spinosum, in the posterior angle near to and in front of the spine; it is a short canal that transmits the middle meningeal vessels and a

recurrent branch Recurrent branch may refer to: * Recurrent branch of the median nerve The recurrent branch of the median nerve is the branch of the median nerve which supplies the thenar muscles. It is also occasionally referred to as the thenar branch of the med ...

from the

. * The foramen petrosum, a small occasional opening, between the foramen spinosum and foramen ovale, for transmission of the lesser petrosal nerve.

Lateral surface

The lateral surface ig. 2is convex, and divided by a transverse ridge, the infratemporal crest, into two portions. * The superior temporal surface, convex from above downward, concave from before backward, forms a part of the temporal fossa, and gives attachment to the temporalis; * the inferior infratemporal surface, smaller in size and concave, enters into the formation of the infratemporal fossa, and, together with the infratemporal crest, serves as an attachment to the lateral pterygoid muscle. It is pierced by the

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 The sphenomandibular ligament (internal lateral ligament) is one of the three ligaments of the temporomandibular joint. It is situated medially to - and generally separate from - the articular capsule of the joint. Superiorly, it is attached to th ...

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 ig. 2 smooth, and quadrilateral in shape, is directed forward and medially and forms the posterior part of the lateral wall of the orbit. * Its upper serrated edge articulates with the orbital plate of the

frontal bone The frontal bone is a bone in the human skull. The bone consists of two portions.'' Gray's Anatomy'' (1918) These are the vertically oriented squamous part, and the horizontally oriented orbital part, making up the bony part of the forehead, pa ...

. * Its inferior rounded border forms the postero-lateral boundary of the inferior orbital fissure. * Its medial sharp margin forms the lower boundary of the

superior orbital fissure The superior orbital fissure is a foramen or cleft of the skull between the lesser and greater wings of the sphenoid bone. It gives passage to multiple structures, including the oculomotor nerve, trochlear nerve, ophthalmic nerve, abducens ...

and has projecting from about its center a little tubercle that gives attachment to the inferior head of the lateral rectus muscle; at the upper part of this margin is a notch for the transmission of a recurrent branch of the lacrimal artery. * Its lateral margin is serrated and articulates with the

zygomatic bone In the human skull, the zygomatic bone (from grc, ζῠγόν, zugón, yoke), also called cheekbone or malar bone, is a paired irregular bone which articulates with the maxilla, the temporal bone, the sphenoid bone and the frontal bone. It is ...

. * Below the medial end of the superior orbital fissure is a grooved surface, which forms the posterior wall of the pterygopalatine fossa, and is pierced by the foramen rotundum.

Margin

Commencing from behind ig. 2 that portion of the circumference of the great wing that extends from the body to the spine is irregular. * Its ''medial half'' forms the anterior boundary of the foramen lacerum, and presents the posterior aperture of the pterygoid canal for the passage of the corresponding nerve and artery. * Its ''lateral half'' articulates, by means of a

synchondrosis A synchondrosis (or primary cartilaginous joint) is a type of cartilaginous joint where hyaline cartilage completely joins together two bones. Synchondroses are different than symphyses (secondary cartilaginous joints) which are formed of fibrocar ...

, with the petrous portion of the temporal, and between the two bones on the under surface of the skull, is a furrow, the sulcus of the auditory tube, for the lodgement of the cartilaginous part of the auditory tube. 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

. 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 The parietal bones () are two bones in the skull which, when joined at a fibrous joint, form the sides and roof of the cranium. In humans, each bone is roughly quadrilateral in form, and has two surfaces, four borders, and four angles. It is named ...

; this region is named the

pterion The pterion is the region where the frontal, parietal, temporal, and sphenoid bones join. It is located on the side of the skull, just behind the temple. Structure The pterion is located in the temporal fossa, approximately 2.6 cm b ...

. Medial to this is a triangular, serrated surface, for articulation with the

; this surface is continuous medially with the sharp edge that forms the lower boundary of the

, and laterally with the serrated margin for articulation with the

Development

The greater wing of the sphenoid bone starts as a separate bone, and is still separate at birth in humans.

Function

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.

Additional images

File:Orbital_bones.png, The seven bones that articulate to form the orbit. File:Gray187.png, Base of skull. Inferior surface. File:Gray189.png, Left infratemporal fossa. File:Gray190.png, The skull from the front. File:Gray310.png, Articulation of the mandible. Medial aspect. File:Gray889.png, Muscles of the right orbit. File:Slide24hhhh.JPG, Greater wing of sphenoid bone File:Slide8jjjj.JPG, Greater wing of sphenoid bone File:Slide1mmmm.JPG, Greater wing of sphenoid bone File:Slide7nnnn.JPG, Greater wing of sphenoid bone File:Slide3pppp.JPG, Greater wing of sphenoid bone

External links

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References

{{Authority control Bones of the head and neck