NASM Muscles EXAM GUIDE [100% Correct]

NASM Muscles EXAM GUIDE [100% Correct] sternocleidomastoid *Ans* Action: flexion of neck forward, rotates the head to opposite shoulder. Scalenes *Ans* Action: elevates ribs 1 and 2, aid in inspiration. Splenius *Ans* Action: extends or hyperextends the head. rotates head to same side of the muscle. Diaphragm *Ans* Action: Respiration, most important muscle in inspiration. Internal intercostal *Ans* Action: draw ribs downward and inward to compress thoracic cavity and force air from lungs; not needed for relaxed expiration. External intercostal *Ans* Action: pulls ribs toward one another to elevate rib cage. Rectus abdominus *Ans* Action: flexes and rotates vertebral column. Transverse abdominus *Ans* Action: compresses abdominal content. Quadratus lumborum *Ans* Action: laterally flexes the spine. Erector spinae *Ans* Action: extends the vertebral column laterally. Major pectoralis *Ans* Action: rotates the arm. Minor pectoralis *Ans* Action: rotates the arm. Serratus anterior *Ans* Action: prime mover that holds the scapula against the ribs. Trapezius *Ans* Action: raises, rotates, and adducts the arm. Levator scapula *Ans* Action: elevates and adducts the scapula. Rhomboid *Ans* Action: stabilize and retract scapula; pulls shoulders back (2 muscles). Latissimus Dorsi *Ans* Action: extends, adducts, and media