Final answer:
A functional junction between bones is called a joint or articulation, with structural classifications based on tissue connections and functional classifications based on range of motion, such as sutures (immobile) and synovial joints (freely movable).
Step-by-step explanation:
A functional junction between bones is called a joint, or articulation. Joints are crucial for permitting various types of movement and providing structural support to the skeletal system. These joints are structurally classified based on their tissue connections—whether fibrous, cartilaginous, or within a joint cavity—and functionally classified based on their range of motion, from immobile (synarthrosis) to slightly mobile (amphiarthrosis) to freely movable (diarthrosis).
For example, sutures found in the skull and gomphoses that anchor the teeth in the jaw are types of fibrous joints. Such fibrous connections allow for stability and protection, as in the case of skull sutures, which are classified as synarthroses due to their immobility and role in protecting the brain. Similarly, synovial joints, like the knee or elbow, enable a wide range of movements and are classified as diarthroses.