Joint actions

1. Joint actions • Flexion – a movement that decreases the angle between the bones at the joint. Eg, bending the leg at the knee or arm at the elbow and, the upward phase of the biceps curl. • Extension- a movement that increases the angle between the bones at the joint; eg, straightening the leg at the knee or, the downward phase of the biceps curl. • Abduction-movement of a body part away from the midline of the body; eg, raising the arm or leg to the side.

2. Joint actions cont • Adduction- the movement of a body part towards the midline of the body. Eg, lowering the arm or leg towards the midline. • Inversion- rotation of the foot to make the sole of the foot face inwards. • Eversion – rotation of the foot to make the sole of the foot face outwards. • Rotation – moving a body part around on its long axis. A full rotation is usually not possible because of ligaments and muscles restricting movement. Eg, the neck turning from one side to the other.

3. Joint actions cont • Circumduction- the circular movement of a body part. Eg, performing arm circles or a softball pitcher’s wind up and release. • Pronation- the rotation of the hand and forearm that causes the hand to face palm downwards. • Supination- rotation of the hand and forearm causing the hand to face palm upwards. • Dorsiflexion – Flexion of the ankle. The top of the foot is pulled towards the tibia. • Plantar flexion- extension of the ankle. Pointing the toes.