Bones move through the action of muscles that pull on them.
The Mechanics of Bone Movement
Muscle Contraction and Tendons
- Skeletal muscles are attached to bones by strong connective tissues called tendons.
- Many skeletal muscles are connected to the ends of bones that meet at a joint.
- Muscles span the joint, connecting the bones involved in the movement.
The Pulling Action
- When a muscle contracts, it shortens.
- This contraction exerts a pull on the attached bone via the tendon.
- The pulling action of muscles on bones results in movement at the joint.
Example
Imagine bending your elbow:
- The bicep muscle (located at the front of the upper arm) contracts.
- This contraction pulls on the tendons that are connected to the bones of your forearm.
- This pulling force causes the forearm to move towards the upper arm at the elbow joint.
In summary, muscles provide the force needed for bone movement through contractions, which pull on tendons attached to the bones. The reference material states directly that "When the muscles contract, they pull on the bones, causing them to move".
