The term "connective tissue sheath" refers to the layer of fibrous tissue that surrounds muscles, nerves and blood vessels throughout the body. Other synonyms for connective tissue sheath include fascia, ligament, tendon, aponeurosis, fibrous membrane, and synovium. Fascia is a broad term used to describe fibrous connective tissue that surrounds and attaches muscles, bones, and organs. Ligaments are fibrous connective tissue that connects bones to other bones or joints. Tendons connect muscles to bones and are responsible for movement. Aponeurosis refers to a sheet of fibrous tissue that attaches muscles to each other or to bones. Fibrous membrane is a thin layer of connective tissue that surrounds organs, muscles, and bones. Synovium is a type of connective tissue found in joints that secretes synovial fluid to lubricate and protect the joint.