What does 'insertion' refer to in muscle structure?

Insertion refers to the more movable attachment of the muscle to the skeleton. In the context of muscle structure, the insertion point is where the muscle attaches to the bone that moves when the muscle contracts. This aspect relates to muscle function, as understanding the insertion is crucial for comprehending how muscles facilitate movement.

When a muscle contracts, it pulls on the bone at its insertion point, enabling various movements across joints. This dynamic is essential in fields such as anatomy, kinesiology, and physical therapy, where the mechanics of movement are studied and applied for rehabilitation and training.

The other options pertain to other aspects of muscle and neuroanatomy. For example, the stationary part of the muscle is known as the origin, not the insertion. The connection between nerves and muscles is through neuromuscular junctions, while the section of the muscle responsible for contraction involves the actual muscle fibers and their interaction with nerve impulses. However, these details describe separate elements rather than defining what insertion specifically refers to.