Shoulder Joint: Actions and Innervations A&N only

Deltoid (All fibers) — Main Action

Abduct the shoulder

Deltoid (Anterior fibers) — Actions

Flex, medially rotate, and horizontally adduct the shoulder

Deltoid (Posterior fibers) — Actions

Extend, laterally rotate, and horizontally abduct the shoulder

Deltoid — Nerve

Axillary C5, 6

Trapezius (Upper fibers) — Bilateral Action

Extend the head and neck

Trapezius (Upper fibers) — Unilateral Action

Laterally flex head/neck to same side, rotate to opposite, elevate/upwardly rotate scapula

Trapezius (Middle fibers) — Actions

Adduct the scapula; stabilize the scapula

Trapezius (Lower fibers) — Actions

Depress the scapula; upwardly rotate the scapula

Trapezius — Nerve

Cranial Nerve XI (accessory), C3, 4

Levator Scapula — Unilateral Action

Elevate/downwardly rotate scapula; laterally flex and same-side rotate head/neck

Levator Scapula — Bilateral Action

Extend the head and neck

Levator Scapula — Nerve

Dorsal scapular C4, 5

Latissimus Dorsi — Actions

Extend, adduct, and medially rotate the shoulder

Latissimus Dorsi — Nerve

Thoracodorsal C6, 7, 8

Teres Major — Actions

Extend, adduct, and medially rotate the shoulder

Teres Major — Nerve

lower subscapular (C6)

Supraspinatus — Actions

Abduct shoulder; stabilize head of humerus in glenoid cavity

Supraspinatus — Nerve

Suprascapular C5, 6

Infraspinatus — Actions

Laterally rotate/adduct shoulder; stabilize head of humerus in glenoid cavity

Infraspinatus — Nerve

Suprascapular C5, 6

Teres Minor — Actions

Laterally rotate/adduct shoulder; stabilize head of humerus in glenoid cavity

Teres Minor — Nerve

Axillary C5, 6

Subscscapularis — Actions

Medially rotate shoulder; stabilize head of humerus in glenoid cavity

Subscapularis — Nerve

Upper and lower subscapular C5, 6

Rhomboid Major — Actions

Adduct, elevate, and downwardly rotate the scapula

Rhomboid Major — Nerve

Dorsal scapular C5

Rhomboid Minor — Actions

Adduct, elevate, and downwardly rotate the scapula

Rhomboid Minor — Nerve

Dorsal scapular C5

Serratus Anterior — Actions

Abduct the scapula, hold the medial border of the scapula against the rib

Serratus Anterior — Nerve

Long thoracic C5, 6, 7

Pectoralis Major (All fibers) — Actions

Adduct and medially rotate shoulder

Pectoralis Major (Upper fibers) — Actions

Flex the shoulder; horizontally adduct the shoulder

Pectoralis Major (Lower fibers) — Action

Extend the shoulder

Pectoralis Major (Upper fibers) — nerve

Lateral pectoral C5, 6, 7

Pectoralis Major (Lower fibers) — Nerve

Lateral and medial pectoral C6, 7, 8, T1

Biceps Brachii — Actions

Flex elbow, supinate forearm, flex shoulder

Biceps Brachii — Nerve

Musculocutaneous C5, 6

Triceps Brachii (All heads) — Action

Extend the elbow

Triceps Brachii (Long head) — Actions

Extend the shoulder

Triceps Brachii — Nerve

Radial C7, 8, T1

Coracobrachialis — Action

flex and adduct shoulder

Coracobrachialis Nerve

Musculocutaneous, C6,7