11: The Muscular System Last updated Save as PDF Page ID 690 OpenStax OpenStax The muscular system is an organ system consisting of skeletal, smooth and cardiac muscles. It permits movement of the body, maintains posture, and circulates blood throughout the body. 11.0: Prelude to the Muscular System 11.1: Interactions of Skeletal Muscles, Their Fascicle Arrangement, and Their Lever Systems 11.2: Naming Skeletal Muscle 11.3: Axial Muscles of the Head, Neck, and Back 11.4: Axial Muscles of the Abdominal Wall and Thorax 11.5: Muscles of the Pectoral Girdle and Upper Limbs 11.6: Appendicular Muscles of the Pelvic Girdle and Lower Limbs