ANATOMY

Detailed explanation-1: -The trapezius elevates, depresses, and retracts the scapula. The descending muscle fibers of the trapezius muscle internally rotate the arms. The transverse muscle fibers retract the scapulae, and the ascending muscle fibers medially rotate the scapulae.

Detailed explanation-2: -The elevation is accomplished by the trapezius, levator scapulae, and rhomboid muscles. Depression is accomplished through the force of gravity and the actions of the latissimus dorsi, serratus anterior, pectoralis major and minor, and the trapezius muscles.

Detailed explanation-3: -The trapezius has three functional parts: an upper (descending) part which supports the weight of the arm; a middle region (transverse), which retracts the scapula; and a lower (ascending) part which medially rotates and depresses the scapula.

Detailed explanation-4: -Scapular Protraction and Retraction Protraction of the scapula is sometimes called abduction of the scapula. The scapula is moved laterally and anteriorly along the chest wall. Muscles: serratus anterior is the prime mover.

Detailed explanation-5: -The lower trapezius is one muscle that plays an important role in scapula movement and positioning, and also dynamic scapula stability. The functional scapula motions of upward rotation, posterior tilt, and external rotation increase the width of the subacromial space during humeral elevation.