Joints 2
Physical Education: AQA GCSE, topic 1.1.7
Ball and Socket Joints
Ball and socket joints are an important type of freely movable joint. A ball and socket joint looks exactly like a ball fitting into a cup. It can move freely in all directions. This type of joint is located in the shoulder and the hip:
Shoulder
- The ball and socket joint here is made up of the humerus (bone in the upper arm), scapula (shoulder blade) and clavicle (collarbone).
- Lets a person move their arm in all directions.
- Can be used to perform a serve in tennis.
Hip
- The ball and socket joint here are made up of the femur (thigh bone) and pelvis.
- Lets a person move their leg in all directions.
- Can be used to perform a lay-up in basketball.
Joint Movements
Joints can move in several different ways.
Flexion
- This is a movement where the angle of the joint decreases.
- Flexion of the elbow = bending the elbow.
- Flexion of the knee = bending the knee.
- Flexion of the hip = raising your knee out in front of you.
- Flexion of the shoulder = raising your arm out in front of you.
Extension
- This is a movement where the angle of the joint increases.
- Extension of the elbow = straightening the elbow.
- Extension of the knee = straightening the knee.
- Extension of the hip = pushing your heel back behind you.
- Extension of the shoulder = pushing your arm back behind you.
Abduction
- This is the movement of a limb away from the midline of the body.
- Abduction of the shoulder = raising your arm out to the side.
- Abduction of the hip = raising your leg out to the side.
- Abduction = take away.
Adduction
- This is the movement of a limb towards the midline of the body.
- Adduction of the shoulder = bringing your arm down to your side.
- Adduction of the hip = bringing your leg down towards your opposing leg.
Rotation
- This is turning a limb around its axis.
- Rotation of the shoulder = forming a circular motion with the arm (as you would when performing a serve in tennis).
- Rotation in the case of a ball and socket joint is known as circumduction.
Plantar flexion
- Movement in the ankle that causes the toes to point towards the ground.
- Plantar flexion = pointed toe.
Dorsiflexion
- Movement in the ankle that causes the toes to point upwards.
Test yourself on Joints 2
What type of joint are ball and socket joints?
What bones make up the ball and socket joint in the hip?
The different types of joint movement
What's the term for the movement of a limb away from the midline of the body?