What connective tissue layer directly surrounds an individual skeletal muscle fiber?

• A. Epimysium
• B. Endomysium
• C. Perimysium
• D. Fascia

Answer: (B)

Understanding how skeletal muscle is organized means recognizing that each muscle fiber has its own delicate connective tissue sleeve. This innermost layer, the endomysium, wraps directly around every single muscle fiber, separating it from its neighbors. It’s a thin network of reticular fibers that houses tiny capillaries and satellite cells, which support nutrient delivery and repair. This close wrapping helps isolate and electrically organize individual fibers while still allowing coordination within the whole muscle, and it provides a conduit to transmit force to the surrounding connective tissues. In contrast, the outer layers—epimysium surrounding the whole muscle, perimysium around each fascicle, and fascia binding muscles together—do not contact individual fibers directly.