1. Skull

2. Objectives
Identify the different bones forming the skull with important foramina.
Differentiate between the bony features of the skull of an adult and infant.

3. The Skull It consists of flat and irregular bones Divides into:
Cranial bones which encase the brain
Facial bones which form the bones of the face
The following must be identified:
Nasion
Inion
Bregma
Lambda
External occipital protuberance
Parietal eminence
Zygomatic arch

4. Nasion
Inion
Bregma
Lambda

5. 5. External occipital protuberance (EOP)
6.Zygomatic arch
( temporal + zygomatic bones)
7. Parietal eminence

6. The Skull Cranial bones include: Facial bones include: (Neurocranium)
Frontal
Ethmoid
Sphenoidal
Occipital
Parietal
Temporal
Facial bones include:
(Viscerocranium)
Maxilla
Zygomatic
Nazal
Palatine
Lacrimal
Inferior concha
Vomer
Mandible

7. Cranial bones include:
(Neurocranium)
Frontal
Ethmoid
Sphenoidal= eagle
Occipital
Parietal
Temporal

8. Temporal bone Landmarks: Squamaus: flat portion
Mastoid process ( behind the ear)
--External auditory meatus: opening to the ear canal
Styloid process
Zygomatic process : process forming part of the cheek
( one part is inside the skull )
Petrous portion (Petrous=pyramid)
Like horizontal pyramid
It's internal, between the sphenoid and occipital

9. Sphenoid bone Landmarks -Body Greater wings Lesser wings
Pterygoid processes
sella turcica ( pituitary fossa) inside the body of sphenoid

10. Ethmoid Bone Occipital bone Landmarks:
Crista galli: upward extension of bone above the cribriform plate
Cribriform plate( on both sides of crista):
Cribriform= sieve ( a lot of openings)
forms the roof of the nasal cavity
Occipital bone
External occipital protuberance (EOP)
Internal occipital protuberance (at the same point of external)
GIF pic

11. Foramina of the Skull Foramina are found within the skull bones
They vary in size and shape
They transmit nerves, blood vessels and dura matter

12. Foramina of the Skull 5 1 R O S
Present in the sphenoid bone 3 2 4

13. Nasal Foramina Lacrimal Bones
Smallest and most fragile bone of the face
+It’s behind the nasal bone

14. Foramina of the Skull
Supraorbital
Infraorbital
Mental

15. Foramina of the Skull 7 12 9,10,11 Carotid artery
+ beginning of jugular vein

16. The Skull Parietal Temporal Squamous Mastoid Styloid Tympanic Petrous
Sphenoid
Greater wing
Lesser wing
Pterygoid process
Body
Occipital

17. The Skull Petrous part of temporal Lesser wing of sphenoid
Body of sphenoid
Pterygoid process
Ethmoid bone
Crista galli
Cribriform plate
Perpendicular plate
Vomer
Palatine bone

18. Cranial Fossa It is the cavity of the skull Divides into:
Anterior cranial fossa
Middle cranial fossa
Posterior cranial fossa

19. Anterior Cranial Fossa
Formed of:
Orbital plate of frontal bone
Cribriform plate of ethmoid
Crista galli
Lesser wing of sphenoid
Occupies:
Frontal lobe of the cerebrum
Optic nerves
Olfactory bulb and tract

20. Middle Cranial Fossa Formed of: Greater wing of sphenoid
Body of sphenoid
Squamous part of temporal bone
Anterior part of petrous bone
It occupies:
Temporal lobe of the cerebrum

21. Posterior Cranial Fossa
Formed of:
Sphenoid part of clivus
Posterior part of petrous bone
Occipital bone
It shows the following land marks:
Groove for transverse sinus
Groove for segmoid sinus
Internal occipital protuberance
It occupies:
Cerebellum
Brain stem

22. Base of The Skull Most of the bones are seen in other views
Fracture base of the skull why?

23. Sutures of the Skull
Sutures are fibrous joints articulating the skull bones
They include:
Coronal
Sagittal
Lambdoid
Pterion

24. Pterion= H-like suture
made by Frontal temporal partial + greater wing of sphenoid
It’s the place of meningeal artery ( above pterion)

25. Skull Fontanelles
Fontanelles are spaces between some of the skull bones of infants.
They permit easy growth of the brain.
They permit overlapping of skull bones during labor.
They include:
1. Anterior Fontanelle ( bregma)
Lies between Frontal and Parietal Bones
Closed by 18 months of age
Posterior Fontanelle (lambda)
Lies between Parietal and Occipital Bones
Closed by end of 1st year
3. Anterolateral Fontanelle
4. Posterolateral Fontanelle

26. The Mandible It is a flat bone Identify the following:
Head(condylar process)
Mandibular notch
Coronoid process
Ramus
Angle
Body
Mylohyoid line
Submandibular fossa
Digastric fossa
Mandibular foramen
Mental foramen