1. Bones: Joints and Injuries

2. Learning Objectives By the end of this class you should understand:
The bones of the three regions of the axial skeleton
The bones that form the three largest joints of the appendicular skeleton
The structure of a major synovial joint
The differences between the different types of joint injuries

4. Axial Skeletal Regions
Skull
Composed of cranium and facial bones
Vertebral column
Supports weight
Houses/protects spinal cord
Ribcage
Protects chest organs
Attaches to arms

5. Skull The skull made of many different bones
Almost all bones (except jawbone) are fused together
These fusions occur at a young age (newborn skulls are unfused so brain can grow)

6. Vertebral column
The vertebral column is made of many vertebrae (singular vertebra)
Vertebrae have two major parts:
Weight-bearing region with cartilage pads between them
A ring of bone that surrounds the spinal cord

7. Vertebra Structure

8. Ribcage
The ribcage is created by 12 pairs of ribs that each attach to a vertebra
Protect thoracic organs (heart, lungs, stomach, liver)
The ribs attach directly or via cartilage to the sternum (breastbone)

9. Appendicular Skeleton
The arms are attached to the axial skeleton via the pectoral girdle
Sternum is the attachment point
The legs are attached to the axial skeleton via the pelvic girdle
The pelvis, or os coxa, is the attachment of the vertebrae to the hip bones

10. Joints Any joint that moves is called a synovial joint
A joint is a meeting point of two or more bones of the human body
There are many classifications of joints
Suture: fused joint (e.g. skull)
Hinge joint: moves in 1 direction (e.g. elbow)
Ball-and-socket joint: moves in 3 dimensions (e.g. shoulder)
Any joint that moves is called a synovial joint

11. Pectoral Girdle
The arm is attached to the axial skeleton at the sternum
The sternum attaches to the clavicle (collar bone)
The clavicle attaches to the scapula (shoulder bone)
The scapula attaches to the humerus (upper arm bone) in a ball-and-socket joint

12. Pectoral Girdle The shoulder is one of the largest joints in the body
Sacrifices strength to gain flexibility
Can move in many directions due to additional motion of clavicle-scapula joint

13. Pelvic Girdle
The pelvis (os coxae) is a fusion of the bottom of the vertebral column with three pairs of hip bones
Together they form a socket that the ball of the femur (thigh bone) fits into
This is a major joint but requires more strength and so has less flexibility

14. Leg Bones The femur is the largest and strongest bone in the body
The femur attaches to the tibia (shin bone) at the knee
The patella (kneecap) is another bone that forms part of this attachment
The lower leg also has the fibula, which does not support any weight, only attachment for muscles

15. Synovial Joints The human body has many movable (synovial) joints
The three most complex and vital ones for movement are the shoulder, hip, and knee
As these joints are more complex, they have more protection

16. Wear and Tear
A synovial joint does not have bone-to-bone contact like a fused joint
Would wear down the bones
Has layers of cartilage and a synovial fluid for lubrication
Loss of protection leads to friction, bone-on-bone grinding, etc

17. Joint Protection
Ligaments and tendons are not permitted to rub against bones
Protected by fluid-filled sacs called bursae (singular bursa)
Inflammation of the bursa is called bursitis
Tear or overstretch of the ligament is called a sprain

18. Anatomy of Major Joints

19. Joint Inflammation A joint may become inflamed with age
Referred to as arthritis
Rheumatoid arthritis is an immune reaction to the joint
Osteoarthritis is a wearing down of the cartilage on a joint and the subsequent thickening of the bone due to friction

20. Next week: muscles!