Shoulder circumduction is a complex, circular movement that combines multiple movements at the glenohumeral joint and the scapulothoracic articulation. It’s not a pure joint movement but rather a coordinated sequence of flexion, abduction, extension, and adduction — essentially tracing a cone with the hand. Here’s a breakdown of the biomechanics: During flexion, the anterior deltoid, clavicular fibres of pectoralis major, biceps brachii, and coracobrachialis are active. The scapula upwardly rotates via the action of serratus anterior and the upper and lower fibres of trapezius. As the arm moves into abduction, the middle deltoid and supraspinatus take over. The scapula continues to rotate upward and laterally, maintaining glenohumeral congruency and range. In extension, the posterior deltoid, latissimus dorsi, and teres major contribute, pulling the humerus posteriorly. The scapula rotates downward slightly, controlled mainly by rhomboids and levator scapulae. Moving into adduction, the pectoralis major (sternal head), latissimus dorsi, and teres major are active again, drawing the arm back toward the body’s midline. The scapula continues downward rotation and returns to its resting position. Throughout the circumduction, the rotator cuff muscles (supraspinatus, infraspinatus, teres minor, and subscapularis) maintain dynamic stability of the humeral head within the glenoid fossa, preventing translation or subluxation. The scapulohumeral rhythm (roughly 2:1 ratio of glenohumeral to scapulothoracic motion) ensures a smooth arc. Disruption in either the shoulder girdle or rotator cuff can compromise this movement. So while circumduction looks like one continuous circle, it’s actually a coordinated chain of movement segments relying on precise neuromuscular control, joint congruency, and scapular kinematics. #osteopathy #manualtherapy #anatomy #rotatorcuff #osteopath #osteopaths - @bradleyblair83