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Small wings of the sphenoid

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Figure 1: Sphenoid bone, upper surface. |- style="text-align: center;" class="hiddenStructure" | colspan="2" |

|- style="text-align: center; line-height: 1;" class="hiddenStructure" | colspan="2" |Figure 2: Sphenoid bone, anterior and inferior surfaces. |- class="hiddenStructure" |Latin |colspan="2"|alæ parvæ |- class="hiddenStructure" | |colspan="2"|[subject #35 ] |- class="hiddenStructure" |Origins |colspan="2"| |- class="hiddenStructure" |Insertions |colspan="2"| |- class="hiddenStructure" |Articulations |colspan="2"| |- class="hiddenStructure" |MeSH |colspan="2"|[] |- class="hiddenStructure" |Dorlands/Elsevier |colspan="2"|[/] |} The small 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. 1].

Surfaces

The superior surface of each is flat, and supports part of the frontal lobe of the brain. The inferior surface forms the back part of the roof of the orbit, and the upper boundary of 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.

It transmits the oculomotor, trochlear, and abducent nerves, the three branches of the ophthalmic division of the trigeminal nerve, some filaments from the cavernous plexus of the sympathetic, the orbital branch of the middle meningeal artery, a recurrent branch from the lacrimal artery to the dura mater, and the ophthalmic vein.

Borders

The anterior border is serrated for articulation with 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).

The small wing is connected to the body by two roots, the upper thin and flat, the lower thick and triangular; between the two roots is the optic foramen, for the transmission of the optic nerve and ophthalmic artery.

Bone: Small wings of the sphenoid

Cranial bones - [http://encycl.opentopia.com/ edit]
occipital bone: Foramen magnum | Squama occipitalis (Inion | Nuchal lines | Planum occipitale | Planum nuchale | Internal occipital protuberance | Sagittal sulcus | Internal occipital crest) | Lateral parts (Hypoglossal canal | Condyloid fossa | Condyloid canal | Jugular process | Jugular tubercle) | Basilar part (Pharyngeal tubercle)

parietal bone: Parietal eminence | Temporal line | Parietal foramen

frontal bone: Squama frontalis (Frontal suture | Frontal eminence | Superciliary arches | Glabella | Supraorbital foramen | Zygomatic process | Sagittal sulcus | Frontal crest | Foramen cecum) | Pars orbitalis (Frontal sinus | Frontonasal duct)

temporal bone: Squama temporalis (Articular tubercle | Suprameatal triangle | Mandibular fossa | Petrotympanic fissure) | Mastoid portion (Mastoid foramen | Mastoid process | Mastoid notch | Occipital groove | Sigmoid sulcus | Mastoid antrum) | Petrous portion (Hiatus of the facial canal | Internal auditory meatus | Subarcuate fossa | Carotid canal | Aqueduct of cochlea | Jugular fossa | Inferior tympanic canaliculus | Mastoid canaliculus | Styloid process | Stylomastoid foramen | Jugular foramen | Petrosquamous suture) | Tympanic part (Suprameatal spine) | Zygomatic process

sphenoid bone: Sphenoidal sinuses | Ethmoidal spine | Optic foramen | Sella turcica | Fossa hypophyseos | Dorsum sellae | Posterior clinoid processes | Carotid groove | Lingula sphenoidalis | Sphenoidal conchæ | Great wings (Spina angularis | Foramen rotundum | Foramen ovale | Foramen Vesalii | Foramen spinosum | Infratemporal crest | Sulcus tubae auditivae | Small wings | Superior orbital fissure | Anterior clinoid process | Optic foramen) | Pterygoid processes (Pterygoid fossa | Scaphoid fossa | Lateral pterygoid plate | Medial pterygoid plate | Pterygoid hamulus | Sphenoidal conchæ | Sphenoidal sinuses)

ethmoid bone: Cribriform plate | Crista galli | Perpendicular plate | Labyrinth | Ethmoid sinus | Uncinate process | Middle nasal concha | Superior meatus | Superior nasal concha | Middle meatus

Facial bones

maxilla: Incisive fossa | Maxillary sinus | Incisive fossa | Canine fossa | Infraorbital foramen | Anterior nasal spine | Alveolar canals | Orbitofrontal cortex | Infraorbital canal | Pterygopalatine canal | Zygomatic process | Agger nasi | Anterior lacrimal crest | Alveolar process | Incisive foramen | Incisive canals | Foramina of Scarpa | Premaxilla | Anterior nasal spine

lacrimal bone: Posterior lacrimal crest

zygomatic bone: Zygomaticofacial foramen | Zygomaticotemporal foramen | Zygomaticoörbital foramina

palatine bone: Pterygopalatine fossa | Pterygoid fossa | Horizontal plate | Posterior nasal spine | Perpendicular plate | Pterygopalatine canal | Sphenopalatine foramen | Pyramidal process | Orbital process | Sphenoidal process

mandible: Symphysis menti | Mental foramen | Mylohyoid line | Ramus mandibulae | Mandibular foramen | Mandibular canal

others: nasal bone | inferior nasal conchae | vomer bone

composite structures

Cranial sutures: Coronal | Lambdoidal | Occipitomastoid | Parietomastoid | Sphenofrontal | Sphenoparietal |Sphenosquamosal | Sphenozygomatic |Squamosal | Zygomaticotemporal | Zygomaticofrontal | Frontal/Metopic | Sagittal | Frontoethmoidal | Petrosquamous | Sphenoethmoidal | Sphenopetrosal

Asterion | Nasion | Pterion | Dacryon | Inferior orbital fissure

 


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