1. The Skeletal System

2. Introduction -The Basics
The skeleton, composed of bones, cartilages, joints, and ligaments, accounts for about 20% of body mass.
There are 206 bones in the human body.

3. The axial skeleton forms the long axis of the body and includes the bones of the skull, vertebral column, and rib cage.
There are 80 bones in the axial skeleton.

4. The Appendicular skeleton consists of the bones of the upper and lower limbs, and the shoulder bones and hip bones.
There are 126 bones in the Appendicular Skeleton.

5. The Axial Skeleton
The skull consists of two sets of bones – the cranium and the facial bones. There are eight cranial bones and fourteen facial bones.
 The joints between bones of the skull are immovable and called sutures.

6. The Cranial Bones of the Skull
Occipital bone
Parietal bones
Frontal bone
Temporal bones
Sphenoid
Ethmoid

7. The Skull
The Adult Skull

8. The Skull
The Adult Skull

9. The Skull
The Adult Skull

10. The Skull Superficial Facial Bones Maxillae = maxillary bones Lacrimal
Nasal
Zygomatic
Mandible

13. The Axial Skeleton
Only the mandible is attached by a freely movable joint.
The hyoid bone is the only bone in the body that does not articulate (match up with) another bone. The hyoid bone acts as an attachment point for several muscles that help with speech and swallowing. The hyoid bone is attached to the skull by ligaments.

15. The Axial Skeleton The vertebral column consists
of vertebrae separated by disks
of fibro-cartilage.
7 cervical vertebrae  
12 thoracic vertebrae  
5 lumbar vertebrae  
The bony thorax forms a cage
to protect major organs

16. SPINAL (VERTEBRAL) COLUMN
The spinal column (or vertebral column) extends from the skull to the pelvis and is made up of 33 individual bones termed vertebrae.

17. The Axial Skeleton The bony thorax is made up of three parts:
1)Sternum
2)Ribs
3)Thoracic vertebrae

18. The Axial Skeleton You have three different types of ribs
True ribs are the first seven pairs of ribs. True ribs attach directly to the sternum by costal cartilages.
False ribs are the next five pairs. They either attach indirectly to the sternum or not at all.
Floating ribs are the last two pairs of false ribs. They lack sternal attachments.

19. The Appendicular Skeleton
The 3 parts of the appendicular skeleton are:
1)Limbs (appendages)
2)Pectoral girdle (shoulder)
3)Pelvic girdle (pelvis)

20. The Appendicular Skeleton
The pectoral girdle (or shoulder) is composed of two bones
1)Clavicle – collarbone
2)Scapula – Shoulder blade
The clavicle and the scapula allow the upper limbs to have free movement

21. The Appendicular Skeleton
The pelvic girdle is made up of the hip bones.
The “hip bones” are composed of three pair of fused bones – the ilium, ischium, and pubic bone.

22. The Appendicular Skeleton
The total weight of the upper body rests on the pelvis.
The pelvic girdle protects several organs – the reproductive organs, the urinary bladder, and part of the large intestine.

23. The Appendicular Skeleton
The hand contains three types
of bones:
1)Carpals – wrists
2)Metacarpals – palm
3)Phalanges - fingers

25. The Appendicular Skeleton
The arm is formed from a single bone, the humerus.
The forearm has two bones: the ulna and radius

26. The Appendicular Skeleton
The thigh has one bone – the femur.
The lower leg has two bones – the tibia and fibula.

27. The Appendicular Skeleton
The foot has three types of bones:
1)Tarsals – ankle
2)Metatarsals – sole
3)Phalanges - toes

29. The Axial Skeleton The axial skeleton
Forms the longitudinal axis of the body
Has 80 bones
The skull:
8 cranial bones
14 facial bones
Bones associated with the skull:
6 auditory ossicles
the hyoid bone

30. The Axial Skeleton The axial skeleton The vertebral column
24 vertebrae (singular = vertebra)
The sacrum
The coccyx
The thoracic cage
24 ribs
The sternum

31. The Axial Skeleton
The Axial Skeleton

32. The Axial Skeleton
Figure 7–1 The Axial Skeleton

33. The Cranial Bones of the Skull
The Occipital Bone
Functions of the occipital bone
Forms the posterior and inferior surfaces of the cranium
Articulations of the occipital bone
Parietal bones
Temporal bones
Sphenoid
First cervical vertebra (atlas)

34. The Axial Skeleton Functions of the Axial Skeleton
Supports and protects organs in body cavities
Attaches to muscles of
Head, neck, and trunk
Respiration
Appendicular skeleton

35. The Skull The skull protects The skull contains 22 bones The brain
Entrances to respiratory system
Entrance to digestive system
The skull contains 22 bones
8 cranial bones:
Form the braincase or cranium
14 facial bones:
Protect and support entrances to digestive and respiratory tracts

36. The Skull
Cranial and Facial Subdivisions of the Skull

37. The Skull Cranial Bones Facial Bones Enclose the cranial cavity
Which contains the brain
And its fluids, blood vessels, nerves, and membranes
Facial Bones
Superficial facial bones
For muscle attachment
Deep facial bones
Separate the oral and nasal cavities
Form the nasal septum

38. The Skull
The Adult Skull

39. The Skull
The Adult Skull

40. The Skull
The Sectional Anatomy of the Skull.

41. The Skull
The Sectional Anatomy of the Skull