Sphenoid bone

Sphenoid Bone AR Atlas

The sphenoid bone articulates with the following bones: the vomer, the ethmoid bone, the frontal bone, the occipital bone, the parietal bone, the temporal bone, the zygomatic bone, and the palatine bone. (1)

• Sphenoid Bone: The Sphenoid bone is situated at the base of the skull. It consists of a body, two great wings, two small wings, and two pterygoid processes.

Body of sphenoid bone

• Body of sphenoid bone: The body of the sphenoid is shaped like a cube and is hollow on the inside (1).
• Sphenoidal yoke: The sphenoidal yoke is an elevated surface located on the superior surface of the sphenoidal body. It is positioned on the midline between the lesser wings at the point where they meet each other. (1)
• Limbus of sphenoid: The limbus of the sphenoid is the border that bounds the sphenoidal yoke posteriorly. (1)
• Chiasmatic sulcus: The chiasmatic sulcus is a horizontal groove positioned behind the sphenoid bone’s limbus. (1)
• Sella turcica: The sella turcica is a depression located posterior to the Chiasmic sulcus. (1)
  • Tuberculum sellae: The tuberculum sellae is a prominence located anterior to sella turcica and posterior to the chiasmic sulcus. (1)
  • Middle clinoid process: The middle clinoid processes are small elevations located on either side of the tuberculum sellae. (1)
  • Hypophysial fossa: The hypophysial fossa is the deepest part of sella turcica. It houses the pituitary gland. (1)
  • Dorsum sellae: The dorsum sellae is a bony plate that represents the posterior border of the sella turcica (1)
  • Posterior clinoid process: The posterior clinoid process prominences on either side of the upper margin of the dorsum sellae. (1)
• Carotid sulcus: The carotid sulcus is a broad groove on the body’s lateral surface. It lodges the carotid artery and the cavernous sinus. (1)
• Sphenoidal lingula: The sphenoidal lingula is a bony ridge located on the posterior part of the lateral surface, on the lateral margin of the carotid sulcus. (1)

• Sphenoidal crest: The sphenoidal crest is a bony ridge located on the body’s anterior surface on the midline. It articulates with the perpendicular plate of the ethmoid (1)
• Sphenoidal rostrum: The sphenoidal rostrum is a spine found on the inferior surface of the body of the sphenoid. It continues the sphenoidal crest and articulates with the vomer. (1)
• Sinus of sphenoid bone: The sinus of the sphenoid bone is an irregular cavity found inside the sphenoid bone’s body. A thin bony plate separates the two sinuses. (1)
  • Opening of sinus of sphenoid bone: The opening of the sinus of sphenoid bone is an irregular opening found on either side of the sphenoidal crest (1)
• Septum of sphenoidal sinuses: The septum of sphenoidal sinuses is a thin bony lamina that separates the sinuses of the sphenoid bone from one another. (1)
• Sphenoidal concha: The sphenoidal conchae are two curved bony plates on either side of the crest covering the sinuses. On their upper part is the opening of the sinus of the sphenoid bone that leads into the sinus. (1)

Lesser wing

• Lesser wing: Two lesser wings originate on the superior anterior part of the body of the sphenoid. They are triangular and project laterally. (1)
• Optic canal: The optic canal is a tunnel located on either side of the prechiasmatic groove. It communicates with the orbit and gives passage to the optic nerve and the ophthalmic artery. (1)
• Anterior clinoid process: The anterior clinoid processes are two bony prominences on either side of the lesser wings. They are positioned on the medial end of the lesser wings’ posterior border. (1)

Greater wing

• Greater wing: The Greater wings are two curved processes that originate on the lateral side of the body of the sphenoid. (1)
• Temporal surface of greater wing: The temporal surface of the greater wing is the surface that is located on the lateral surface of the greater wing, above the infratemporal crest . It takes part in the formation of the temporal fossa. (1)
• Infratemporal surface of greater wing: The infratemporal surface of the greater wing is the surface located below the infratemporal crest on the lateral surface of the greater wing. It takes part in the formation of the infratemporal fossa. On this surface, we can find the openings foramen ovale and foramen spinosum. (1)
• Infratemporal crest: The infratemporal crest is a ridge that divides the lateral surface of the greater wing of the sphenoid bone into two surfaces. The upper surface is the temporal surface of the greater wing, and the lower surface is the infratemporal surface of the greater wing. (1)
• Maxillary surface of greater wing: . It is the surface of the greater wing that is in oriented towards the maxilla bone. (6)
• Orbital surface of greater wing: The orbital surface of the greater wing is a smooth surface that forms the lateral wall and the posterior part of the orbit. (1)
• Zygomatic margin of greater wing: The zygomatic margin is the margin that articulates with the zygomatic bone (1)
• Frontal margin of greater wing: The frontal margin is the margin that articulates with the frontal bone. (1)
• Parietal margin of greater wing: The parietal margin is the margin that articulates with the parietal bone. (1)
• Squamosal margin of greater wing: The squamosal margin is the margin that articulates with the temporal bone. (1)

• Cerebral surface of greater wing: The cerebral surface of the greater wing is the superior surface of a great sphenoidal wing. It takes part in forming the middle fossa of the skull. (1)
• Foramen rotundum: The foramen rotundum is located on the anteriomedial part of the greater wing. It gives passage to the maxillary nerve. (1)
• Foramen ovale: The foramen ovale is an oval shaped foramen that is located posterolaterally to foramen rotundum. It gives passage to the mandibular nerve and accessory meningeal artery. (1)
• Sphenoidal emissary foramen: The sphenoidal emissary foramen is an inconstant small aperture located medial to the foramen ovale. (1)
• Foramen spinosum: Foramen spinosum is a short tunnel located at the posterior angle of the cerebral surface of the great wing, anterior to the spine of the sphenoid bone. (1)
• Foramen petrosum: Foramen Petrosum is a passage situated next to foramen ovale. It gives way to the Lesser Petrosal Nerve (1)
• Spine of sphenoid bone: The spine of the sphenoid bone is an irregular projection that is positioned lateral to the foramen spinosum (4)
• Sulcus of auditory tube: The sulcus of the auditory tube attaches the cartilaginous part of the auditory tube. It is located on the lateral part of the posterior margin of the greater wing (1)

Pterygoid process

• Pterygoid process: The pterygoid processes are too bony processes that originate in the area where the body meets the great wings. Each pterygoid process consists of a lateral and medial plate fused anterosuperiorly. (1)
• Lateral pterygoid plate: The lateral pterygoid plate is the thin plate that is located laterally. Its lateral surface takes part in forming the infratemporal fossa, and its medial surface takes part in forming the pterygoid fossa. (1)
• Medial pterygoid plate: The medial pterygoid plate is the plate that is located medially. The lateral surface takes part in the formation of the pterygoid fossa. (1)
• Pterygoid notch: The pterygoid notch is a slit that is located at the inferior part of the pterygoid processes. It separates the lateral plate from the medial plate. (1)

• Pterygoid fossa: The pterygoid fossa is a fossa that is located posteriorly on the pterygoid process. (1)
• Scaphoid fossa: The scaphoid fossa is a shallow, oval depression on the medial surface of the greater wing of the sphenoid bone. (1)
• Pterygospinous process: The pterygospinous process is a pointed projection located on the rear border of the sphenoid bone’s lateral pterygoid plate (3)

Vaginal process of the sphenoid bone

• Vaginal process of sphenoid bone: The vaginal processes of the sphenoid bone are two bony projections found on each side of the sphenoidal rostrum. They articulate with the sphenoidal process of the palatine bone and the ala of the vomer. (1)
• Palatovaginal groove: The palatovaginal groove, located on the sphenoid bone, gives rise to the palatovaginal canal by connecting the palatine bone with the vaginal process of the sphenoid bone. (24)
• Vomerovaginal groove: The vomerovaginal groove, located on the pterygoid process, forms the vomerovaginal canal when it is joined by the vomer bone. (24)

• Pterygoid hamulus: The pterygoid hamulus is a hook-like process that is located at the inferior end of the medial pterygoid plate. (1)
  • Groove of pterygoid hamulus: The groove of pterygoid hamulus, is a groove situated on the hamulus. (24)
• Pterygoid canal: The pterygoid canal is the tunnel that passes through the base of the pterygoid process. It has an anterior orifice opening on the anterior surface and a posterior orifice that opens on the posterior surface. (1)

Bibliography

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The structure and organization of anatomical terms used in this text follow the guidelines provided by FIPAT (2019) in their publication: FIPAT. (2019). Terminologia Anatomica (2nd ed.). FIPAT.library.dal.ca. Federative International Programme for Anatomical Terminology. Retrieved May 7, 2023, from https://fipat.library.dal.ca/TA2/