1. Organization of the Skeleton

2. The Human Skeleton 206 bones Divided into two portions.
Axial Skeleton- Contains the bones which are in the mid-vertical axis of the body.
Appendicular Skeleton- Bones which are outside the mid-vertical axis, associated with the appendages.

3. Axial Skeleton Skull Contains 22 bones.
Bones of the skull include; (8) cranial, (13) facial and the (1) mandible.
Sutures- Connection between the bones of the skull.
Sinus-Chamber- Located in the skull, are lined with mucous membranes, and filled with air.
Connect with the nasal cavity to drain fluids and reduce the weight of the skull.

4. Axial Skeleton
Cranium (8) bones
1.Frontal Bone- Large bone forming the anterior part of the skull (forehead).
Orbits: Eye sockets, partially formed by the frontal bone.
Supraorbital Foramen: Hole above each orbital where blood vessels pass.

5. Axial Skeleton Cranium
2.Parietial Bone(s)-Two bones which form most of the superior/lateral cranium.
Meet at the top of the skull at the sagittal suture.
Meet the frontal bone at the coronal suture.

6. Axial Skeleton Cranium
3.Occipital Bone- Thick bone which forms the posterior wall and floor of the cranium.
Meets the parietal bone at the lambdoid suture.
Foramen Magnum- Opening for the spinal cord.
Occipital Condyles- Processes that articulate with the first vertebrae, to allow head movement.

7. Axial Skeleton Cranium
4.Temporal Bone(s)- Two bones on either side of the cranium, below the parietal bones.
Meet the parietal bones at the squamous suture.
Styloid Process- Serves as an anchor for muscles of the tongue and pharynx.

8. Axial Skeleton Cranium
5. Sphenoid Bone- Butterfly shaped bone that forms the lower lateral walls and floor of the cranium, also the posterior walls of the orbits.
Optic foramen- Location of the optic nerve passage.
6.Ethmoid Bone- Small bone anterior to the sphenoid bone.
Forms sections of the cranial floor, orbital walls, and nasal cavity.

9. Axial Skeleton Facial Bones
Contains 13 immovable bones and a movable mandible.
1.Maxillary Bone(s)- Two bones on each side of the face that form the upper jaw.
2.Palatine Bone(s)- Two L-shaped bones that are posterior to the maxillary bones.
Forms the roof of mouth and floor of the nasal cavity.

10. Axial Skeleton Facial Bones
3.Zygomatic Bone(s)- Two bones on the side of the face that form the cheeks.
4.Nasal Bone(s)- Two small rectangular bones that meet to form the bridge of the nose.
5.Lacrimal Bone(s)- Two fingernail shaped bones, form part of the orbits medial walls.

11. Axial Skeleton Facial Bones
6.Vomer- Single bone along the midline within the nasal cavity.
Meets with ethmoid to form the nasal septum, divides the nasal cavity in half.
7.Inferior Nasal Concha- Two thin scroll-like bones attached to the lateral walls of the nasal cavity.
Forms shelves to channeled air into the nasal cavity.

12. Axial Skeleton Facial bones
8.Mandible-Single lower jaw bone, articulates with the temporal bones.
Only movable bone of the skull.
Forms TMJ (temporal-mandibular joint)
Lock Jaw
Dislocated Jaw

13. Axial Skeleton Hyoid Bone
Single bone that doesn’t articulate with any other bones.
Horse-shoe shaped
supports the tongue and provides attachments for muscles.

14. Axial Skeleton Vertebral Column
Strong flexible rod that supports the trunk, while allowing for movement.
Extends from the skull to the pelvis.
Made of irregular bones known as vertebrae.
Between each vertebrae is an intervertebral disc.
The adult vertebral column contains 26 vertebrae (after fusion).

15. Axial Skeleton Structure of typical vertebrae:
Body: Thick, disc-shaped front portion, designed for supporting weight.
Vertebral Arch: Forms a ring to hold the spinal cord called the Vertebral Foramen.
Seven processes arise from the vertebral arch and serve for joint formation or muscle attachment.

16. Axial Skeleton Types of Vertebrae and their Structures.
Cervical- (7) Vertebrae of the neck region, the support the head.
Transverse foramen- small hole that permits the passage of arteries to the brain.
Atlas- First cervical vertebrae that connects with the occipital condyles of the cranium. Allows for up and down movement of Skull.
Axis- Second cervical vertebrae that contains a tooth like projection called the:
Odontoid process- It projects up through the rings of the atlas and allows for twisting of the head.

17. Axial Skeleton Types of Vertebrae and their Structures.
Thoracic- (12) Only vertebrae that articulate with the ribs. (middle of back)
Lumbar- (5) Vertebrae that are large and thick, this is due to the increase in the body weight they support. (lower back).
Sacrum- Large triangular bone that forms the posterior part of the pelvis made of (5) vertebrae fused together.
Sacral Canal: contains the spinal cord.
Coccyx- 3-5 fused bones that is attached to the sacrum by ligaments. (tail bone)

18. Axial Skeleton Thoracic Cage
Formed by thoracic vertebrae, sternum, and the ribs.
Conical, basket-shaped structure
(cone shaped).
Partially encloses the internal structures of the chest.
Supports the upper limbs.

19. Axial Skeleton Thoracic Cage
Sternum- AKA breast bone, It’s a flat, narrow bone at the center of the chest.
Articulates with the clavicles on one end.
Articulates with the ribs via the costal cartilage.
Consists of three (3) parts:
Manubrium- Superior part
Body- Large middle part
Xiphoid Process- Small pointy inferior end.

20. Axial Skeleton Thoracic Cage Ribs (12) sets in every individual.
Attach to the thoracic vertebrae in the back and the sternum in the front.
True Ribs- First seven (7) pair, connects directly to the sternum via the costal cartilage.
False Ribs- Remaining five (5) pair, have an indirect connection or no connection at all to the sternum.
Floating Ribs- Last two (2) or sometimes three (3) pairs of ribs, have no connection at all to the sternum.