ABSTRACT
Any movement at the shoulder joint is accompanied by movements of the pectoral girdle (scapula and clavicle). Muscles arise from the torso and skull to attach to the clavicle (1), scapula and humerus. The scapula may be: ● rotated upward during abduction by trapezius (2),
serratus anterior (3) ● rotated downward during adduction by pectoralis
major (4,5) and minor (9), latissimus dorsi (10) ● protracted by pectoralis major and minor, serratus
anterior ● retracted by rhomboids (11), trapezius, levator
scapulae. The muscles combine to brace the scapula against the thoracic wall and hold its position to provide a platform for the upper limb when carrying weights or pushing. Many are accessory muscles of respiration. Anterior muscles that attach to the humerus flex the shoulder joint, posterior muscles extend it. ● Trapezius (accessory (XI)) – from skull, cervical
spines via ligamentum nuchae and thoracic spines to scapular spine, acromion process, and lateral onethird of clavicle (posterior aspect).
