Upper Limb Muscles

Muscles acting on the pectoral girdle

Levator scapulae, Rhomboid major, Rhomboid minor, Serratus anterior, Trapezius, Pectoralis minor

Levator scapulae

Elevates, adducts (retracts) and inferiorly rotates scapula; laterally flexes neck to same side when scapula is fixed

Rhomboid major

Elevates, adducts (retracts), inferiorly rotates and stabilizes scapula

Rhomboid minor

Elevates, adducts (retracts), inferiorly rotates and stabilizes scapula

(Same as rhomboid major)

Serratus anterior

Stabilizes, superiorly rotates and protracts scapula (prime mover of scapula protraction)

Trapezius OIA

origin: Occipital bone; ligamentum nuchae; spinous processes of C7-T12

insertion: Clavicle; acromion process and spine of scapula

action:

• Superior fibers – elevate and superiorly rotate scapula

• Middle fibers – retract (adduct) scapula

• Inferior fibers – depress and superiorly rotate scapula

Pectoralis minor OIA

origin: Ribs 3-5

insertion: Coracoid process of scapula

action: Protracts and depresses scapula

Muscles acting on the arm at the glenohumeral joint

Deltoid, coracobrachialis, pectoralis major, latissimus dorsi, teres major, supraspinatus, infraspinatus, teres minor, subscapularis

Deltoid OIA

origin: Acromial end of clavicle; acromion and spine of scapula

insertion: Deltoid tuberosity of humerus

action:

• Anterior fibers – flex and medially rotate arm

• Middle fibers – prime mover of arm abduction

• Posterior fibers – extend and laterally rotate arm

coracobrachialis OIA

origin: Coracoid process of scapula

insertion: Middle medial shaft of humerus

action: Adducts and flexes arm

pectoralis major IA

insertion: Greater tubercle of humerus

action: Adducts, medially rotates and flexes arm (prime mover of arm flexion)

Latissimus dorsi IA

insertion: Intertubercular sulcus of humerus

action: Adducts, medially rotates and extends arm (prime mover of arm extension)

Teres major

Adducts, medially rotates, and extends arm

Supraspinatus OIA

origin: Supraspinous fossa of scapula

insertion: Greater tubercle of humerus

action: Abducts arm

Infraspinatus OIA

origin: Infraspinous fossa of scapula

insertion: Greater tubercle of humerus

action: Laterally rotates arm

Teres minor OIA

origin: Upper dorsal lateral border of scapula

insertion: Greater tubercle of humerus

action: Laterally rotates arm

subscapularis OIA

origin: Subscapular fossa of scapula

insertion: Lesser tubercle of humerus

action: Medially rotates arm

Rotator cuff muscles + function

• supraspinatus, infraspinatus, teres minor, subscapularis (SITS)

• Stabilize the shoulder joint

Anterior compartment of the arm

Biceps brachii, Brachialis, Brachioradialis

Biceps brachii OIA

origin:

• Long head – supraglenoid tubercle of scapula;

• Short head – coracoid process of scapula

insertion: Radial tuberosity

action: Flexes and supinates forearm; long head also flexes arm

Brachialis OIA

origin: Anterior humerus

insertion: Coronoid process of ulna

action: Flexes forearm

Brachioradialis

Flexes forearm

Posterior compartment of the arm

Triceps brachii

Triceps brachii OIA

Origin: 

• Long head – infraglenoid tubercle

• lateral head – posterior humerus above radial groove

• medial head – posterior humerus below radial groove

Insertion: Olecranon of ulna

Action: Primary extensor of forearm; long head also extends and adducts arm

Superficial layer of anterior forearm

Flexor carpi ulnaris, Palmaris longus, Flexor carpi radialis, Pronator teres

Flexor carpi ulnaris OA

Origin: Medial epicondyle of humerus

Action: Flexes and adducts hand

Palmaris longus OA

Origin: Medial epicondyle of humerus

Action: Weak hand flexor

Flexor carpi radialis OA

Origin: Medial epicondyle of humerus

Action: Flexes and abducts hand

Pronator teres OIA

Origin: Medial epicondyle of humerus

Insertion: Lateral surface of radius

Action: Pronates forearm

Intermediate layer of anterior forearm muscles

Flexor digitorum superficialis

Flexor digitorum superficialis OIA

Origin: Medial epicondyle of humerus; coronoid process of ulna

Insertion: Middle phalanges of fingers 2-5

Action: Flexes hand, 2nd-5th MP joints and PIP joints

Deep layer of anterior forearm muscles

Flexor digitorum profundus, Pronator quadratus

Flexor digitorum profundus OIA

Origin: Anteromedial surface of ulna; interosseous membrane

Insertion: Distal phalanges of digits 2-5

Action: Flexes hand, 2nd-5th MP joints; PIP joints, and DIP joints

Pronator quadratus

Prime mover of forearm pronation

Flexor retinaculum

Deep fascia that holds tendons against the bone during contraction

Superficial layer of posterior forearm muscles

Extensor carpi radialis longus, Extensor carpi radialis brevis, Extensor digitorum, Extensor carpi ulnaris

Extensor carpi radialis longus OA

Origin: Lateral supracondylar ridge of humerus 

Action: Extends and abducts hand

Extensor carpi radialis brevis OA

Origin: Lateral epicondyle of humerus 

Action: Extends and abducts hand

Extensor digitorum OA

Origin: Lateral epicondyle of humerus 

Action: Extends hand and 2nd-5th MP joints, PIP joints and DIP joints

Extensor carpi ulnaris OA

Origin: Lateral epicondyle of humerus 

Action: Extends and adducts hand

Extensor retinaculum

Deep fascia that holds extensor tendons close to the wrist joint to prevent them from “bowing” during wrist extension

Deep layer of posterior forearm muscles

Abductor pollicis longus, Extensor pollicis brevis, Extensor pollicis longus

Abductor pollicis longus

Extends and abducts thumb

Extensor pollicis brevis

Extends thumb

Extensor pollicis longus

Extends thumb