Muscles of the Upper Limb
Muscles Of The Shoulder
Muscle: Deltoid
Origin: Lateral third of clavicle, acromion, and spine of scapula
Insertion: Deltoid tuberosity of humerus
Nerve: Axillary, C5, C6
Action: Abducts, adducts, flexes, extends, and rotates arm medially
Muscle: Infraspinatus
Origin: Infraspinous fossa of scapula
Insertion: Middle facet of greater tubercle of humerus
Nerve: Suprascapular, C5, C6
Action: Rotates arm laterally; helps to hold humeral head in glenoid cavity of scapula
Muscle: Latissimus dorsi
Origin: Spines of T7-T12 thoracolumbar fascia, iliac crest, ribs 9-12
Insertion: Floor of bicipital groove of humerus
Nerve: Thoracodorsal C6, C7, C8
Action: Extends, adducts, and medially rotates humerus; raises body towards arms during climbing
Muscle: Pectoralis major
Origin: Clavicular head anterior surface of medial half of clavicle
Insertion: Lateral lip of intertubercular groove of humerus
Nerve: Lateral and medial pectoral nerves; clavicular head C5 and C6, sternocostal head C7, C8 and T1
Action: Abducts, medially rotates humerus; draws scapula anteriorly and inferiorly
Muscle: Pectoralis minor
Origin: 3rd to 5th ribs near the costal cartilages
Insertion: Medial border and superior surface of coracoid process of scapula
Nerve: Medial pectoral nerve C8 and T1
Action: Stabilizes scapula against thoracic wall
Muscle: Subscapularis
Origin: Subscapular fossa
Insertion: Lesser tubercle of humerus
Nerve: Upper and lower subscapular, C5, C6, C7
Action: Medially rotates arm and adducts it; helps to hold humeral head in glenoid cavity
Muscle: Supraspinatus
Origin: Supraspinous fossa of scapula
Insertion: Superior facet of greater tubercle of humerus
Nerve: Suprascapular C4, C5, C6
Action: Initiates and assists deltoid in abduction of arm and acts with rotator cuff of muscles
Muscle: Teres minor
Origin: Superior portion of lateral border of scapula
Insertion: Inferior facet of greater tubercle of humerus
Nerve: Axillary, C5, C6
Action: Laterally rotates arm; helps to hold humeral head in glenoid cavity of scapula
Muscle: Teres major
Origin: Dorsal surface of inferior angle of scapula
Insertion: Medial lip of intertubercular groove of humerus
Nerve: Lower subscapular, C6, C7
Action: Adducts and rotates arm medially
Muscles Of The Arm
Muscle: Anconeus
Origin: Lateral epicondyle of humerus
Insertion: Lateral surface of olecranon and superior part of posterior surface of ulna
Nerve: Radial, C7, C8, and T1
Action: Assists triceps in extending forearm; abducts ulna during pronation
Muscle: Biceps brachii
Origin: Long head, supraglenoid tubercle; short head, coracoid process
Insertion: Radial tuberosity of radius
Nerve: Musculocutaneous, C5, C6
Action: Flexes arm and forearm, supinates forearm
Muscle: Brachialis
Origin: Distal anterior surface of humerus
Insertion: Coronoid process of ulna and ulnar tuberosity
Nerve: Musculocutaneous, C5, C6
Action: Flexes forearm in all positions
Muscle: Coracobrachialis
Origin: tip of coracoid process of scapula
Insertion: Middle third of medial surface of humerus
Nerve: Musculocutaneous, C5, C6, C7
Action: Flexes and adducts arm
Muscle: Triceps
Origin: Long head, infraglenoid tubercle; lateral head, superior to radial groove of humerus; medial head to radial groove
Insertion: Posterior surface of olecranon process of ulna
Nerve: Radial, C6, C7, C8
Action: Chief extensor of forearm at elbow
Muscles Of The Anterior Forearm
Muscle: Flexor carpi radialis
Origin: Medial epicondyle of humerus
Insertion: Bases of second and third metacarpals
Nerve: Median, C6, C7
Action: Flexes forearm; flexes and abducts hand
Muscle: Flexor carpi ulnaris
Origin: Humeral head, medial epicondyle of humerus; ulnar head, olecranon and posterior border of ulna
Insertion: Pisiform bone, hook of hamate, and base of fifth metacarpal
Nerve: Ulnar, C7, C8
Action: Flexes and adducts hand, flexes forearm
Muscle: Flexor digitorum profundus
Origin: Anteromedial surface of ulna, interosseous membrane
Insertion: Base of digital phalanges of medial four fingers
Nerve: Ulnar and medial, C8, T1
Action: Flexes distal interphalangeal joints and hand
Muscle: Flexor digitorum superficialis
Origin: Medial epicondyle, coronoid process of ulna, superior anterior border of radius
Insertion: Middle phalanges of finger
Nerve: Median, C7, C8, T1
Action: Flexes proximal interphalangeal joints; flexes hand at wrist
Muscle: Flexor pollicis longus
Origin: Anterior surface of radius and adjacent interosseus membrane
Insertion: Base of distal phalanx of thumb
Nerve: Median, C8. T1
Action: Flexes thumb
Muscle: Palmaris longus
Origin: Medial epicondyle of humerus
Insertion: Distal half of flexor retinaculum, palmar aponeurosis
Nerve: Median, C7, C8
Action: Flexes hand at wrist and forearm
Muscle: Pronator quadratus
Origin: Anterior surface of distal ulna
Insertion: Anterior surface of distal radius
Nerve: Anterior interosseous nerve from median C8, and T1
Action: Pronates forearm; helps hold radius and ulna together
Muscle: Pronator teres
Origin: Medial epicondyle of humerus and coronoid process of ulna
Insertion: Middle of lateral surface of radius
Nerve: Median, C6, C7
Action: Pronates and flexes arm at elbow
Muscles Of The Posterior Forearm
Muscle: Abductor pollicis longus
Origin: Interosseous membrane, middle third of posterior surface of radius and ulna
Insertion: Lateral surface of base of first metacarpal
Nerve: Radial, deep branch, posterior interosseous nerve C7, C8
Action: Abducts thumb and hand
Muscle: Articularis cubiti
Origin: Distal portion of posterior aspect of shaft of humerus
Insertion: Posterior fibrous capsule of elbow joint
Nerve: Radial, C7, C8
Action: Retracts posterior joint capsule during extension of elbow
Muscle: Brachioradialis
Origin: Lateral supracondylar ridge of humerus
Insertion: Base of radial styloid process
Nerve: Radial, C5, C6, C7
Action: Flexes forearm
Muscle: Extensor carpi radialis brevis
Origin: Lateral epicondyle of humerus
Insertion: Posterior base of third metacarpal
Nerve: Radial, deep branch, C7, C8
Action: Extends fingers and abducts hands at wrist
Muscle: Extensor carpi radialis longus
Origin: Lateral supracondylar ridge of humerus
Insertion: Dorsum of base of second metacarpal
Nerve: Radial, C6, C7
Action: Extends and abducts hand at wrist joint
Muscle: Extensor carpi ulnaris
Origin: Lateral epicondyle and posterior surface of ulna
Insertion: Base of fifth metacarpal
Nerve: Radial, deep branch, posterior interosseous nerve C7, C8
Action: Extends and adducts hand at wrist joint
Muscle: Extensor digiti minimi
Origin: Common extensor tendon and interosseous membrane
Insertion: Extensor expansion, base of middle and distal phalanges
Nerve: Radial, deep branch, posterior interosseous nerve C7, C8
Action: Extends little finger
Muscle: Extensor digitorum
Origin: Lateral epicondyle of humerus
Insertion: Extensor expansion, base of middle and digital phalanges
Nerve: Radial, deep branch, posterior interosseous nerve C7, C8
Action: Extends fingers and hand at wrist
Muscle: Extensor indicis
Origin: Posterior surface of ulna and interosseous membrane
Insertion: Extensor expansion of index finger
Nerve: Radial, deep branch, posterior interosseous nerve C7
Action: Extends index finger; helps extend hand
Muscle: Extensor pollicis brevis
Origin: Interosseous membrane and posterior surface of middle third of radius
Insertion: Base of proximal phalanx of thumb
Nerve: Radial, deep branch, posterior interosseous nerve C7, C8
Action: Extends proximal phalanx of thumb and abducts hand
Muscle: Extensor pollicis longus
Origin: Interosseous membrane, middle third of posterior surface of ulna
Insertion: Base of distal phalanx of thumb
Nerve: Radial, deep branch, posterior interosseous nerve C7, C8
Action: Extends distal phalanx of thumb and abducts hand
Muscle: Supinator
Origin: Lateral epicondyle of humerus, radial collateral and anular ligaments, crest of ulna
Insertion: Lateral side of upper part of radius
Nerve: Radial, deep branch, C5, C6
Action: Supinates forearm
Muscles Of The Hand
Muscle: Abductor digiti minimi
Origin: Pisiform, pisohamate ligament, flexor retinaculum
Insertion: Medial side of base of proximal phalanx of little finger
Nerve: Ulnar, deep branch, C8, T1
Action: Abducts little finger
Muscle: Abductor pollicis brevis
Origin: Flexor retinaculum, scaphoid and trapezium
Insertion: Lateral side of base of proximal phalanx of thumb
Nerve: Median, recurrent branch, C8, T1
Action: Abducts thumb
Muscle: Adductor pollicis
Origin: Capitate and bases of second and third metacarpals, (oblique head); palmar surface of third metacarpal (transverse head)
Insertion: Medial side of base of proximal phalanx of the thumb
Nerve: Ulnar, deep branch, C8, T1
Action: Adducts thumb towards middle digit
Muscle: Dorsal interossei (4)
Origin: Adjacent sides of metacarpal bones
Insertion: Extensor expansions and bases of phalanges of digits 2-4
Nerve: Ulnar, deep branch, C8, T1
Action: Abducts fingers, flexes metacarpophalangeal joints; extends interphalangeal joints
Muscle: Flexor digiti minimi brevis
Origin: Flexor retinaculum and hook of hamate
Insertion: Medial side of base of proximal phalanx of little finger
Nerve: Ulnar, deep branch, C8, T1
Action: Flexes proximal phalanx of little finger
Muscle: Flexor pollicis brevis
Origin: Flexor retinaculum and trapezium
Insertion: Base of proximal phalanx of thumb
Nerve: Median, recurrent branch, C8, T1
Action: Flexes thumb
Muscle: Lumbricals (4)
Origin: 1-2 lateral, 3-4 medial side of tendons of flexor digitorum profundus
Insertion: Lateral side of extensor expansion
Nerve: Median (two lateral), ulnar (two medial)
Action: Flexes metacarpophalangeal joints, extends interphalangeal joints
Muscle: Opponens digiti minimi
Origin: Flexor retinaculum and hook of hamate
Insertion: Medial side of fifth metacarpal
Nerve: Ulnar, deep branch, C8, T1
Action: Opposes little finger with thumb
Muscle: Opponens pollicis
Origin: Flexor retinaculum and tubercle of scaphoid and trapezium
Insertion: Lateral side of first metacarpal
Nerve: Median, recurrent branch, C8, T1
Action: Opposes thumb to other digits
Muscle: Palmar interossei (3)
Origin: Palmar surface of 2nd, 4th, and 5th metacarpals (unipennate muscles)
Insertion: Bases of proximal phalanges on same sides as their origins; extensor expansion
Nerve: Ulnar, deep branch, C8, T1
Action: Adducts fingers; flexes metacarpophalangeal joints; extends interphalangeal joints
Muscle: Palmaris brevis
Origin: Ulnar side of flexor retinaculum, palmar aponeurosis
Insertion: Skin of ulnar side of hand
Nerve: Ulnar, superficial, T1
Action: Wrinkles skin on palmar side of hand