Joints
Science: KS3, topic 1.6.8
Joints
A joint is where two bones meet. Joints allow movement in the body.
Ball and socket joints
- Ball and socket joints allow full movement.
- Examples of ball and socket joints include the hip and shoulder.
- One bone is ball-shaped and the other is like a bowl.
- It is a bit like if you clench your fist and hold it in your other hand.
Hinge joints
- Hinge joints are like door hinges.
- They only allow movement forwards and backward.
- Examples include the elbow and the knee.
How do joints move?
- Muscles can only pull. They can not push.
- To move a joint, muscles must work in pairs.
- These are called antagonistic muscles.
- When one antagonistic muscle contracts the other muscle in the pair relaxes and vice versa.
- Examples include:
- Bicep and triceps.
- Quadricep and hamstring.
Test yourself on Joints
Hinge joints allow movement in which direction?
Why can the shoulder move in more directions than the elbow?