Anatomical Terminology Basics

9. Muscles

Part of understanding how muscles move bones is knowing where muscles attach. The "origin" of a muscle is the bone that stabilizes it when it contracts, while the "insertion" is where it attaches and causes movement. The insertion is usually a connection between the muscle, a tendon, and bone. In most cases, the origin is a larger bone with more mass than the insertion so it can support the muscle contraction and intended movement.