What structure encloses the entire muscle?

The correct answer, which is the epimysium, refers to the layer of connective tissue that surrounds the entire muscle. This structure plays a vital role in protecting and supporting the muscle while also contributing to its overall structure. The epimysium is essential for maintaining the integrity of the muscle fibers and acts as a conduit for nerves and blood vessels that supply the muscle, allowing for efficient function and health.

In contrast, the perimysium is the connective tissue that surrounds bundles of muscle fibers, called fascicles, while the endomysium envelops individual muscle fibers. Fascia, on the other hand, is a broader term that encompasses connective tissue structures that may cover muscles, groups of muscles, or entire muscle groups but is not specific to the individual muscle like the epimysium. Understanding the hierarchical organization of muscle connective tissues helps clarify how each layer contributes to muscle function and protection.