Muscles acting on the Shoulder and Arm

Teres minor (origin)

lateral border of scapula

Teres minor (insertion)

greater tubercle of humerus

Teres minor (action)

extends, laterally rotates, and adducts the arm (stabilizes shoulder joint)

Teres minor (innervation)

Axillary nerve

Trapezius (origin)

occipital protuberance, nuchal ligament, spinner processes of C7-T12

Trapezium (insertion)

clavicle, acromion process, spine of scapula

Trapezium (action)

extends and abducts head, rotates and adducts scapula, fixes scapula

Latissimus dorsi (origin)

T7-12, L1-5, sacrum, iliac crest, ribs 10-12

Latissimus dorsi (insertion)

Intertubercular groove of the humerus

Latissimus dorsi (action)

extends, adducts, and medially rotates arm; depresses shoulder

Deltoid (origin)

clavicle, acromion process, spine of scapula

Deltoid (insertion)

deltoid tuberosity of humerus

Deltoid (action)

abducts, flexes, and extends arm; medially and laterally rotates arm

Deltoid (innervation)

Axillary nerve

Rhomboideus major (origin)

spines of T1-4

Rhomboideus major (insertion)

inferior, medial border of scapula

Rhomboideus major (action)

adducts scapula

Rhomboideus minor (origin)

nuchal ligament, spines of C6-7

Rhomboideus minor (insertion)

medial border of scapula at scapular spine

Rhomboideus minor (action)

adducts scapula

Levator scapulae (origin)

C1-4

Levator scapulae (insertion)

superior angle of scapula

Levator scapulae (action)

elevates scapula, abducts and rotates neck

Supraspinatus (origin)

supraspinous fossa

Supraspinatus (insertion)

greater tubercle of humerus

Supraspinatus (action)

abducts arm (stabilizes shoulder joint)

Supraspinatus (innervation)

suprascpular nerve

Infraspinatus (origin)

infraspinous fossa

Infraspinatus (insertion)

greater tubercle of humerus

Infraspinatus (action)

extends and laterally rotates arm (stabilizes shoulder joint)

Infraspinatus (innervation)

Suprascapular nerve

Subscapularis (origin)

subscapular fossa

Subscapularis (insertion)

lesser tubercle of humerus

Subscapularis (action)

extends and medially rotates arm (stabilizes shoulder joint)

Subscapularis (innervation)

subscapular nerve

Teres major (origin)

lateral border of scapula

Teres major (insertion)

crest of lesser tubercle of humerus

Teres major (action)

extends, adducts and medially rotates arm

Teres major (innervation)

subscapular nerve

Triceps brachii (origin)

infraglenoid tuberosity of scapula, lateral and posterior surface of humerus

Triceps brachii (insertion)

olecranon process of ulna

Triceps brachii (action)

extends and adducts arm, extends forearm

Triceps brachii (innervation)

radial nerve

Pectoralis major (origin)

clavicle, sternum, cartilages of ribs 1-7

Pectoralis major (insertion)

crest of greater tubercle of humerus

Pectoralis major (action)

flexes, adducts, and medially rotates arm

Pectoralis major (innervation)

anterior thoracic nerves

Pectoralis minor (origin)

Ribs 3-5

Pectoralis minor (insertion)

coracoid process of scapula

Pectoralis minor (action)

depresses glenoid cavity, raises ribs 3-5

Pectoralis minor (innervation)

anterior thoracic nerves

Biceps brachii (origin)

supraglenoid tubercle, coracoid process of scapula

Biceps brachii (insertion)

radial tuberosity

Biceps brachii (action)

flexes arm, flexes forearm, supinates hand

Biceps brachii (innervation)

Musculocutaneous nerve

Coracobrachialis (origin)

coracoid process of scapula

Coracobrachialis (insertion)

midmedial shaft of humerus

Coracobrachialis (action)

flexes and adducts arm

Coracobrachialis (innervation)

Musculocutaneous nerve

Brachialis (origin)

anterior, distal surface of humerus

Brachialis (insertion)

coronoid process of ulna

Brachialis (action)

flexes forearm

Brachialis (innervation)

Musculocutaneous and radial nerves

Brachioradialis (origin)

lateral supracondylar ridge of humerus

Brachioradialis (insertion)

styloid process of radius

Brachioradialis (action)

flexes forearm

Brachioradialis (innervation)

radial nerve

Supinator (origin)

lateral epicondyle of humerus, anterior ulna

Supinator (insertion)

proximal radius

Supinator (action)

supinates hand

Supinator (innervation)

radial nerve

Pronator Teres (origin)

medial epicondyle of humerus, coronoid process of ulna

Pronator Teres (insertion)

lateral, middle shaft of radius

Pronator Teres (action)

pronates hand, flexes forearm

Pronator Teres (innervation)

median nerve

Pronator quadratus (origin)

Distal part of anterior ulna

Pronator quadratus (insertion)

distal radius

Pronator quadratus (action)

pronates hand

Pronator quadratus (innervation)

median nerve (anterior interosseous branch)