Axial Skelton

1. CHAPTER 7“The Axial Skeleton”Review your A&P revealed discsCourse objectives:Define and identify the bones of the axial skeleton

2. Axial Skelton • 80 total bones • consists of the bones that form the long axis of the body including the: • Skull (total 28 with ear bones) • Vertebral column [(total 26) C7;T12; L5; S1; Co1] • Bony thorax [ribs and sternum (total 25)] • Hyoid bone (1)

3. Bones of the axial skeleton

4. Axial Skelton

5. Skull BonesReview A&P revealed discsanimation of skull • the skull has two major divisions: Cranium and Facial bones Cranium – the 8 bones that enclose the brain. -1 occipital, 1 frontal, 2 parietal, 2 temporal, 1 sphenoid and 1 ethmoid. • These typical flat bones of the cranium are connected by a special kind of joint called a suture (Synarthroses).

6. Cranial bones

7. Cranial Bones Midsaggital section

8. Cranial Bones Midsaggital section

9. Cranium • Made up of 2 major divisions: • Calvarium (skull cap) • Base • Base contains three large depressions (fossa): • Anterior cranial fossa where the frontal lobes sit • Middle cranial fossa where the temporal lobes sit • Posterior cranial fossa where the cerebellum sits

10. Cranial Bones

11. Cranial Bones

12. Sutures/Sutural Bones • Sutures (synarthroses) are immovable fibrous joints. -all bones in the skull, except for the jaw, are united by sutures. The major sutures are: -Coronal -Sagittal -Squamous -Lamboid Sutural bones- small bones that occur within the sutures, especially the lamboid suture. They are not present in all people.

13. Sutures/Sutural Bones

14. Facial bones • There are 14 bones that can be thought of as creating the face. • As part of this function they provide: - protection for many sense organs, -anchors for many muscles -the openings for air and food to pass. Facial Bones 2-maxillae; 2-palatine; 2-nasal; 2- zygomatic; 2-lacrimal; 2-inf nasal conchae; 1- vomer; and 1-mandible

18. Sphenoid bone Looks like a Bat in flight. Greater and lesser wings; optic foramen; sella turcica, superior orbital fissure. Dorsal view.

19. Sphenoid bone Dorsal view Anterior view

20. Ethmoid bone • Anterior to sphenoid bone forms anterior base of skull and nasal cavity. • Cribriform plate. • Crista gali • Perpendicular plate

21. Ethmoid bone

22. Ethmoid bone

23. Foramen/ Orbits • Foramen: Special openings in bones where nerves, blood vessels enter into the bone cavity. - Ex.: Foramen magnum, Supraorbital Infraorbital, Mental, Jugular, Olfactory, Mandibular • Orbits: Cone shaped bony cavities that hold the eyes, fat, occular muscles and tear glands.

24. Bones of the eye orbit

25. Meatus/ Sinuses • Meatus: a canal or opening into bone - Ex.: external auditory, internal acoustic • Sinus: cavities within bones filled with air. -Ex.: frontal, ethmoid, sphenoid and maxillary sinuses

26. Cranial sinuses

27. Cranial fossa Fossa are depressions or cavities in the skull.

28. The Fetal Skull • Sutures are called fontanels in fetus. • Fontanels -Frontal (anterior) -Occipital (posterior) -Sphenoidal (anterior lateral) -Mastoid (posterior lateral)

29. The Fetal Skull

30. The Fetal Skull