Movements of the Shoulder Joint

The shoulder joint has more freedom of movement than any other joint in the body.

Types of Movement

Four groups of movement occur at the glenohumeral joint:

Movement	Plane	Axis
Flexion / Extension	Sagittal (parallel to glenoid surface)	Frontal axis
Abduction / Adduction	Frontal (plane of scapular body)	Sagittal axis
Medial / Lateral rotation	Transverse	Vertical axis
Circumduction	All planes	—

Note: Movements are described relative to the plane of the glenoid cavity (oblique, ~45° to sagittal), not standard anatomical planes.

Flexion: arm moves forwards and medially
Extension: arm moves backwards and laterally
Abduction: arm moves anterolaterally away from trunk
Adduction: arm moves posteromedially toward trunk
Medial rotation: hand moves across chest (demonstrated with elbow at 90°)
Lateral rotation: hand moves away from body (demonstrated with elbow at 90°)

Movement	Main Muscles	Accessory Muscles
Flexion	Pectoralis major (clavicular), anterior deltoid	Coracobrachialis, short head of biceps
Extension	Posterior deltoid, latissimus dorsi	Teres major, long head of triceps
Adduction	Pectoralis major (sternocostal), latissimus dorsi	Teres major, coracobrachialis, short head of biceps, long head of triceps
Abduction	Deltoid (lateral fibres), supraspinatus	Serratus anterior (90°–180°), trapezius (90°–180°)
Medial rotation	Subscapularis, pectoralis major, anterior deltoid, latissimus dorsi, teres major	—
Lateral rotation	Infraspinatus, teres minor, posterior deltoid	—

Both supraspinatus and deltoid initiate and sustain abduction from 0°–90°
Serratus anterior + upper and lower fibres of trapezius are essential for abduction from 90°–180°
Circumduction = sequential flexion → abduction → extension → adduction (or reverse)