Final answer:
The epimysium is the connective tissue layer beneath the fascia that encases the whole muscle, providing structural support.
Step-by-step explanation:
The layer of connective tissue that is underneath the fascia and surrounds the muscles is known as the epimysium. Other layers such as the perimysium and endomysium also play significant roles in the structure of muscles.
While the perimysium covers bundles of muscle fibers known as fascicles, the endomysium wraps around each individual muscle fiber. The epimysium encases the whole muscle, contributing to the structure and support of the muscle tissue.