The part of the muscle farthest from the skeleton, also known as the movable attachment, is the ______.

• A. Insertion
• B. Origin
• C. Tendon
• D. Muscle Belly

Answer: (A)

Insertion is the attachment of a muscle to the bone that moves when the muscle contracts. This attachment is typically the part farthest from the skeleton, because the muscle shortens and pulls the insertion toward the origin, which remains relatively fixed during most movements. The origin is the fixed anchor, the tendon connects the muscle to bone, and the muscle belly is the fleshy middle portion. For example, when the biceps contracts, the insertion on the radius moves the forearm toward the shoulder, producing elbow flexion.