A fascia is a layer of fibrous tissue. A fascia is a structure of connective tissue that surrounds muscles, groups of muscles, blood vessels, and nerves, binding some structures together, while permitting others to slide smoothly over each other. Various kinds of fascia may be distinguished. They are classified according to their distinct layers, their functions and their anatomical location: superficial fascia, deep (or muscle) fascia, and visceral (or parietal) fascia.