Muscles pull, bones move

The idea

Muscles produce movement by pulling on bones: when a muscle contracts, the tendon attaching it transmits the force to the bone, causing movement at a joint.

Lifting a cup

To lift a cup you bend your arm at the elbow. A bone is hard, and it cannot move itself.

What do you think makes the arm bone move?

• A muscle pulling on it
• The bone pushing itself
• The skin stretching

Pull the bone

Slide the muscle pull to make the arm bend.

A pull through the tendon

The muscle pulled on the bone. The tendon is the strong, flexible band that attaches the muscle to the bone, and it passes the force on, so the bone moved at the elbow joint.

Muscles produce movement by pulling on bones: when a muscle contracts, the tendon attaching it transmits the force to the bone, causing movement at a joint.

Notes

Muscles move bones by pulling: a contracting muscle's force goes through the tendon to the bone, and it moves at a joint.

Check yourself

How do muscles produce movement?

When a muscle contracts, which part transmits the force to the bone?

Where does the movement happen when the muscle pulls the bone?

Which order is correct?

• By pulling on bones — correct. Yes!
• By pushing on bones. Muscles produce movement by pulling on bones.
• By sending messages to the bones. Sending messages is done by nervous tissue. Muscles pull on bones.
• The ligament. A ligament connects bone to bone. It is the tendon that attaches the muscle to the bone.
• The tendon — correct. Yes!
• The cartilage. Cartilage has a soft, jelly-like matrix that gives flexibility and cushioning. The tendon attaches the muscle to the bone.
• Inside the muscle. The muscle contracts, but the bone moves at a joint.
• Inside the tendon. The tendon transmits the force. The movement of the bone happens at a joint.
• At a joint — correct. Yes!
• The muscle contracts, the tendon transmits the force, the bone moves at a joint — correct. Yes!
• The bone moves, then the tendon transmits the force, then the muscle contracts. The muscle contracts first, and its pull travels through the tendon to the bone.
• The tendon contracts, the muscle transmits the force, the bone moves. It is the muscle that contracts. The tendon attaches it to the bone and transmits the force.