Rotational and translational components

Question 1

What occurs with forces that run along the bone?

Answer 1

• Acts at the same point as the original force.
• Pulls the bone towards or away from the joint.
• No turning effect.
• Zero moment arm.

Question 2

What occurs when a force is right-angled to a joint?

Answer 2

• Acts at the same point as the original force.
• Pure turning effect. (torque)

Question 3

What occurs if a force runs along the segment through the axis of rotation?

Answer 3

• Zero rotational component.
• Purely translational.
• Either compress the joint by pushing the segment into the axis of rotation.
• Or pill the bone away from the axis by tensing the joint and pulling on its ligaments.

Question 4

What occurs if a force is perpendicular to a segment?

Answer 4

• Zero translational effect.
• Purely rotational.