Sphenoid bone (osteology)

Head and Neck

(Osteology)

Group 4 Presentation

Sphenoid Bone

1Group 4 presentaion

Group names

• Abdiwadud Ahmed (Karama)• Abdiaziz Abdirashid Ahmed • Sa’id Abdalle Abdirahman

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Sphenoid bone

• Lies at the base of the skull in front of petrous part of temporal bone and basilar part of occipital bone.

• It resembles a bat with outstretching wings.

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Parts of sphenoid bone

• Body: forms the central part• 2 Greater wings Project laterally from the

• 2 lesser wings sides of the body

• 2 pterygoid processes

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Body

Lesser wings

Greater wing

Pterygoidprocess

Body

• Cubical in shape and possesses 6 surfaces:• Superior, 2 lateral, anterior, inferior and

posterior.• Contains two large air sinuses, separated

from each other by a septum.

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Surfaces

• Superior (cerebral) surface: articulates anteriorly with the cribriform plate of ethmoid bone.

• Features • Sella turcica Jugum• Tuberculum sellae Prechiasmatic groove

• Optic canal• 2 anterior clinoid processes• 2 posterior clinoid processes • Dursum sellae

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Cont…

• Lateral surface: 2 united with the greater wings and medial pterygoid plate

• Processes:• Carotid sulcus• Lingula • Anterior surface: it has:-• Sphenoidal crest • Sphenoidal air sinuses

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Cont….

• Inferior surfaces: forms the roof of the posterior part corresponding nasal cavity.

• Posterior surface:• Articulates with the basilar part of occipital bone

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Anterior clinoid process

Posterior clinoid process

Sellae turcica

Dursum Sellae

Carotid sulcus

Jugum

Optic canal

Prechiasmatic sulcus

Tuberculum sellae

Lingula

Greater wings

• Are two strong processes which curve upwards and laterally from the sides of the body.

• It has:• 2 surfaces: cerebral (superior), lateral and

inferior (orbital) surfaces • 2 borders: posterior and squamosal

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Surfaces

• Cerebral surface: forms the part of the floor of middle cranial fossa.

• Foramina:• Foramen rotundom• Foramen ovale • Foramen spinosum

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Cont…..

• Lateral surface: convex in its general outline

• Inferior surface (orbital): directs forwards and medially and forms postero-lateral wall of orbital cavity

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Borders

1. Posterior border: its medial border is non-articular and forms the anterior border of the foramen lacerum

• Its lateral part articulates with petrous part of temporal bone

2. Squamosal border: articulates with squamous part of temporal bone.

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Foramen rotundom

Foramen Ovale

Formamen spinosum

Foramen lacerum

Squamosal border

Posterior border

Lesser wings

• Are two triangular plates projecting laterally from upper and anterior parts of the body of sphenoid bone.

• Connected to the body by two roots b/w which lies optic canal.

• Have 2 surfaces and 2 borders.

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Surfaces

1. Cerebral surface: smooth and supports part of the frontal lobe of the brain.

2. Inferior surface: forms posterior part of roof of orbit and upper boundary of superior orbital fissure.

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Borders 1. Anterior border: articulates with posterior

border of orbital plate of frontal lobe.2. Posterior border: its medial end forms the

anterior clinoid process, to which is attached the anterior end of free border of tentorium cerebri.

• Optic canal: lies b/w the 2 roots of lesser wings.• Superior orbital fissure: triangular passage lying

b/w the greater and lesser wings and leading from cranial to orbital cavity

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Superior orbital fissure

Anterior border

Posterior border

Optic canal

Pterygoid process

• On each side descending perpendicularly from the region where the greater wing of sphenoid unite with the body of shenoid bone.

• Consists of lateral and medial plates, where upper part is fussed in front.

• pterygoid fissure: an angular gap which separates the plates below, its margins articulate with perpendicular process of palatine bone

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1. Lateral pterygoid plate: Lateral surface forms part of medial infra-temporal fossa and gives origin to lateral pterygoid muscle.

Medial surface forms lateral wall of pterygoid fossa and gives origin to medial pterigoid muscle.2. Medail pterygoid plate: The inferior end of the medial pterygoid plate is prolonged as a curved spike of bone, the pterygoid hamulus.

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Views of the bone in detail

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Anterior view

1. Lesser wing2. Superior O. fissure3. Orbital surafe4. Temporal surface 5. Infratemporal surace6. Spine of sphenoid7. Maxillary surface8. Pterygoid process9. Lateral pterygoid plate10. Pterygoid notch11. Medial pterygoid plate12. Groove for pterygoid humulus 13. Pterygoid humulus14. Body of sphenoid

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15.Crest of sphenoid16.Rostrum17.Vaginal process18.Pterygoid canal19.Foramen rotundum20.Conchae 21.Sphenoid sinus22.Frontal margin23.Zygomatic margin24.Pareital margin34. Optic canal

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Posterior view

1. Lesser wing 2. Superior O. fissure6. Spine 9. Lateral pterygoid p.10. Pterygoid notch11. Medial pterygoid p.13. Pterygoid humulus14. Body18. Pterygoid canal

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19. Foramen rotundum25. Anterior clinoid process 26. Posterior clinoid process27. Dorsum sellae28. Carotid groove 29. Lingula 30. Scaphoid process31. Superior surface of greater W.32. Squamous margin 34. Opticcanal

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Superior veiw

1. Lesser wing2. Superior O. fissure6. Spine 13. Humulus19. Foramen rotundum22. Frontal margin24. Parietal margin25. Anterior C. process26. Posterior C. process 27. Dorsum sellae28. Carotid groove

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29. Lingula 31. Superior surface G. wing32. Squamous margin34. Optic canal 35. Jugum36. Prechiasmatic sulcus 37. Tuberculum sellae 38. Pitutary fossa 39. Foramen ovale40. Ala of vemor

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Inferior view

1. Lesser wing 2. Superior O. fissure3. Orbital surface4. Temporal surface5. Infratemporal S.6. Spine 7. Maxillary sufrace9. Lateral pterygoid plate11. Medial pterygoid plate

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12. Groove of pterygoid humulus13. Pterygoid humulus14. Body15. Crest 16. Rostrum20. Conchea 21. Sphenoid sinus 32. Squamous margin33. Groove for Auditory tube39. Foramen ovale40. Foramen spinosum

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Lateral view

4. Temporal surface6. Spine 9. L. pterygoid plate13. Pterygoid humulus14. Body22. Frontal margin23. Zygomatic margin

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24. Pareital margin25. Anterior C. process26. Posterior C. process 27. Dorsum sellae28. Carotid groove32. Squamous margin 38. Pitutary fossa

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