1. The Skeletal System - Joints
Where two bones meet in the body a joint is formed. Joints where movements (such as flexion, extension and adduction) occur are known as synovial joints.
There are three types of synovial joint that you need to know about and each allows different movements.
Ball & Socket joint: examples include the shoulder and the hip.
Pivot: example is the neck joint.
Hinge: examples include the knee and elbow.
(GCSE PE: Unit 1.2.2)

2. Different Types of Joint
The three different joints have different characteristics:
1) Ball & Socket joint:
- Its movement is like a PS4 controller joystick
It allows movement in a number of directions (including rotation, adduction and abduction in the shoulder and flexion/extension in the hip).
2) Pivot:
Its movement is similar to a washing machine drum.
Allows a medium amount of movement (including rotation in the neck).
3) Hinge:
Movement is like a door opening an closing.
Only allows movement in one direction (flexion/extension in elbow/knee)
(GCSE PE: Unit 1.2.2)

3. Parts of a Joint
Each joint, regardless of type, has the same key parts that you need to know:

4. Parts of a Joint 1) Tendons: 2) Ligaments: 3) Hyaline Cartilage:
Strong, non-elastic tissue that attaches muscles to bone.
2) Ligaments:
Tough, elastic fibre that attach bone to bone at a joint.
3) Hyaline Cartilage:
Tissue found at the end of bones that stops bones banging together – Mr Yates has damaged this in his femur which is why he walks with so much $WAG (*limps).
4) Synovial Fluid:
Found inside the joint, it works like oil and keeps the joint working smoothly.
5) Synovial Membrane:
This is the lining inside a joint and is the place where synovial fluid is produced.

5. The Effects of Exercise & Diet on the Skeleton
Exercise and diet can both have an effect on our skeletal system.
DIET. Eating foods high in calcium (milk, cheese) leads to more calcium being stored in the bones. This makes the bone stronger, helping it to support muscles and protect vital organs.
DIET. Eating foods high in vitamin D can help the body absorb more calcium.
EXERCISE: Weight-bearing exercise (walking, running, weight-lifting) where there is some impact on the bones can help increase bone density. A higher bone density reduces the chance of injury, improves posture and reduces the chance of osteoporosis (where bones become weak and fragile).
EXERCISE: Exercising for a long period of time also helps strengthen the tendons and ligaments. These means joints have more support and become more stable. It also increases the production of synovial fluid, making the joint more flexible.
(GCSE PE: Unit 1.2.2)

6. Injuries & the Skeletal System
We have looked at muscle injuries but sport can also lead to bone/joint injuries:
BONE INJURIES:
Injury
Description
Fracture
Happens when a force on the bone is stronger than the bone itself. There are FOUR types (commonly known as breaks)
1. Compound (open) Fracture
The bone breaks completely and the broken end comes through the skin.
2. Simple (closed) Fracture
The bone breaks completely but it all happens under the skin.
3. Greenstick Fracture
Pressure or impact buckles or bends a bone, cracking it slightly but not causing a total break.
4. Stress Fracture
Caused by overuse. Starts off as a small crack but gets worse as you continue to use it.
(GCSE PE: Unit 1.2.2)

7. Injuries & the Skeletal System
We have looked at muscle injuries but sport can also lead to bone/joint injuries:
JOINT INJURIES:
Injury
Description
Overuse Injury
(Soft Tissue)
Using a joint repeatedly can cause tendons to become inflamed (tennis elbow)
Dislocation
One of the bones at a joint comes out of place during a fall or a blow to the area.
Sprains
Ligament fibres get torn when a joint is overstretched or twisted.
Torn Cartilage
Small tears appear in the cartilage at the end of a bone.
(GCSE PE: Unit 1.2.2)

8. Ice: Applying ice to the injury helps prevent swelling and pain.
Treating Injuries
In order to treat soft tissue joint injuries you should use the RICE procedure:
Rest: Firstly you should rest the inured part, preventing further damage.
Ice: Applying ice to the injury helps prevent swelling and pain.
Compression: Putting a bandage or strapping around the injured area helps with support and should reduce internal bleeding/swelling.
Elevate: It is important to lift the injured part to reduce swelling and painful throbbing (resting it on a box/bench/chair etc). Ideally the injured part should be raised above the level of the heart as this will stop internal bleeding.
(GCSE PE: Unit 1.2.2)