Upper Extremity Muscles Flashcards
Extensor Digitorum
Origin: Lateral epicondyle of humerus
Insertion: Extensor expansions of medial four digits
Action: Extends medial four digits at metacarpophalangeal joints; Extends hand at wrist joint
Innervation: Posterior interosseous nerve (C7 and C8), the continuation of the deep branch of the radial nerve
Arterial Supply: Interosseous recurrent and posterior interosseous arteries
Subscapularis
Origin: Subscapular fossa of scapula
Insertion: Lesser tuberosity of humerus
Action: Medially rotates arm and adducts it; helps to hold humeral head in glenoid cavity of scapula
Innervation: Upper and lower subscapular nerves (C5, C6 and C7)
Arterial Supply: Subscapular artery
Pectoralis Minor
Origin: 3rd to 5th ribs near their costal cartilages
Insertion: Medial border and superior surface of coracoid process of scapula
Action: Stabilizes scapula by drawing it inferiorly and anteriorly against thoracic wall
Innervation: Medial pectoral nerves; clavicular head (C8 and T1)
Arterial Supply: Pectoral branch of the thoracoacromial trunk
Extensor Pollicis Longus and Brevis
Brevis
Origin: Posterior surfaces of radius and interosseous membrane
Insertion: Base of proximal phalanx of thumb
Action: Extends proximal phalanx of thumb at carpometacarpal joint
Innervation: Posterior interosseous nerve (C7 and C8), the continuation of the deep branch of the radial nerve
Arterial Supply: Posterior interosseous artery
Longus
Origin: Posterior surface of middle 1/3 of ulna and interosseous membrane
Insertion: Base of distal phalanx of thumb
Action: Extends distal phalanx of thumb at carpometacarpal and interphalangeal joints
Innervation: Posterior interosseous nerve (C7 and C8), the continuation of the deep branch of the radial nerve
Arterial Supply: Posterior interosseous artery
Serratus Anterior
Origin: Superolateral surfaces of upper 8 or 9 ribs at the side of chest
Insertion: Vertebral border of scapula
Action: Draws scapula forward and upward; abducts scapula and rotates it; stabilizes vertebral border of scapula
Innervation: Long thoracic nerve (C5, C6, C7)
Arterial Supply: Circumflex scapular artery
Deltoid
Origin: Lateral third of clavicle, acromion, and spine of scapula
Insertion: Deltoid tuberosity of humerus
Action: Anterior part: flexes and medially rotates arm; Middle part: abducts arm; Posterior part: extends and laterally rotates arm
Innervation: Axillary nerve (C5 and C6)
Arterial Supply: Deltoid branch of thoracoacromial artery
Triceps Brachii
Origin: Long head: infraglenoid tubercle of scapula; Lateral head: posterior surface of humerus, superior to radial groove; Medial head: posterior surface of humerus, inferior to radial groove
Insertion: Proximal end of olecranon process of ulna and fascia of forearm
Action: Chief extensor of forearm; long head steadies head of abducted humerus
Innervation: Radial nerve (C6, C7 and C8)
Arterial Supply: Branches of deep brachial artery
Abductor Pollicis Brevis
Origin: Flexor retinaculum and tubercles of scaphoid and trapezium
Insertion: Lateral side of base of proximal phalanx of thumb
Action: Abducts thumb and helps oppose it
Innervation: Recurrent branch of median nerve (C8 and T1)
Arterial Supply: Superficial palmar branch of the radial artery
Flexor Digitorum Superficialis
Origin: Humeroulnar head: medial epicondyle of humerus, ulnar collateral ligament, and coronoid process of ulna; Radial head: superior half of anterior border of radius
Insertion: Bodies of middle phalanges of digits 2 - 5
Action: Flexes middle phalanges at proximal interphalangeal joints of medial four digits; acting more strongly, it also flexes proximal phalanges at metacarpophalangeal joints and hand
Innervation: Median nerve (C7, C8 and T1)
Arterial Supply: Ulnar artery
Abductor Digiti Minimi
Origin: Pisiform
Insertion: Medial side of base of proximal phalanx of little finger
Action: Abducts little (5th) finger
Innervation: Deep branch of ulnar nerve (C8 and T1)
Arterial Supply: Ulnar artery
Opponens Digiti Minimi and Opponens Pollicis
ODM
Origin: Hook of hamate and flexor retinaculum
Insertion: Medial border of 5th metacarpal
Action: Draws 5th metacarpal anteriorly and rotates it, bringing little finger (5th digit) into opposition with thumb
Innervation: Deep branch of ulnar nerve (C8 and T1)
Arterial Supply: Ulnar artery
Pollicis
Origin: Flexor retinaculum and tubercles of scaphoid and trapezium
Insertion: Lateral side of 1st metacarpal
Action: Draws 1st metacarpal laterally to oppose thumb toward center of palm and rotates it medially
Innervation: Recurrent branch of median nerve (C8 and T1)
Arterial Supply: Superficial palmar branch of the radial artery
Teres Major
Origin: Dorsal surface of inferior angle of scapula
Insertion: Medial lip of intertubercular groove of humerus
Action: Adducts and medially rotates arm
Innervation: Lower subscapular nerve (C6 and C7)
Arterial Supply: Subscapular and circumflex scapular arteries
Brachioradialis
Origin: Proximal 2/3 of lateral supracondyle ridge of humerus
Insertion: Lateral surface of distal end of radius
Action: Flexes forearm
Innervation: Radial nerve (C5, C6 and C7)
Arterial Supply: Radial recurrent artery
Abductor Pollicis Longus
Origin: Posterior surfaces of ulna, radius and interosseous membrane
Insertion: Base of 1st metacarpal
Action: Abducts thumb and extends it at carpometacarpal joint
Innervation: Posterior interosseous nerve (C7 and C8), the continuation of the deep branch of the radial nerve
Arterial Supply: Posterior interosseous artery
Latissimus Dorsi
Origin: Spinous processes of inferior 6 thoracic vertebrae, thoracolumbar fascia, iliac crest, and inferior 3 or 4 ribs
Insertion: Floor of intertubercular groove of humerus
Action: Extends, adducts, and medially rotates humerus; raises body toward arms during climbing
Innervation: Thoracodorsal nerve (C6, C7, and C8)
Arterial Supply: Thoracodorsal artery
Dorsal Interosseous Muscles
Origin: Dorsal 1 - 4: Adjacent sides of two metacarpals (bipennate muscles)
Insertion: Dorsal 1 - 4: Extensor expansions and bases of proximal phalanges of digits 2 - 4
Action: Dorsal 1 - 4: Abduct digits from axial line and act with lumbricals to flex metacarpophalangeal joints and extend interphalangeal joints
Innervation: Deep branch of ulnar nerve (C8 and T1)
Arterial Supply: Dorsal 1 - 4: Dorsal and palmar metacarpal arteries
Pronator Quadratus
Origin: Distal 1/4 of anterior surface of ulna
Insertion: Distal 1/4 of anterior surface of radius
Action: Pronates forearm; deep fibers bind radius and ulna together
Innervation: Anterior interosseous nerve from median nerve (C8 and T1)
Arterial Supply: Anterior interosseous artery
Extensor Carpi Radialis Brevis
Origin: Lateral epicondyle of humerus
Insertion: Base of 3rd metacarpal
Action: Extend and abduct hand at wrist joint
Innervation: Deep branch of radial nerve (C7 and C8)
Arterial Supply: Radial artery
Coracobrachialis
Origin: Tip of coracoid process of scapula
Insertion: Middle third of medial surface of humerus
Action: Helps to flex and adduct arm
Innervation: Musculocutaneous nerve (C5, C6 and C7)
Arterial Supply: Muscular branches of brachial artery
Pectoralis Major
Origin: Clavicular head: anterior surface of medial half of clavicle; Sternocostal head: anterior surface of sternum, superior six costal cartilages, and aponeurosis of external oblique muscle
Insertion: Lateral lip of intertubercular groove of humerus
Action: Adducts and medially rotates humerus; draws scapula anteriorly and inferiorly; Acting alone: clavicular head flexes humerus and sternocostal head extends it
Innervation: Lateral and medial pectoral nerves; clavicular head (C5 and C6, sternocostal head (C7, C8, and T1)
Arterial Supply: pectoral branch of the thoracoacromial trunk
Teres Minor
Origin: Superior part of lateral border of scapula
Insertion: Inferior facet on greater tuberosity of humerus
Action: Laterally rotate arm; helps to hold humeral head in glenoid cavity of scapula
Innervation: Axillary nerve (C5 and C6)
Arterial Supply: Subscapular and circumflex scapular arteries
Brachialis
Origin: Distal half of anterior surface of humerus
Insertion: Coronoid process and tuberosity of ulna
Action: Major flexor of forearm – flexes forearm in all positions
Innervation: Musculocutaneous nerve (C5 and C6)
Arterial Supply: Muscular branches of brachial artery, recurrent radial artery
Trapezius
Origin: Medial third of superior nuchal line; external occipital protruberance, nuchal ligament, and spinous processes of C7 - T12 vertebrae
Insertion: Lateral third of clavicle, acromion, and spine of scapula
Action: Elevates, retracts and rotates scapula; superior fibers elevate, middle fibers retract, and inferior fibers depress scapula; superior and inferior fibers act together in superior rotation of scapula
Innervation: Spinal root of accessory nerve (CN XI) (motor) and cervical nerves (C3 and C4) (pain and proprioception)
Arterial Supply: Transverse certical artery
Rhomboid Major and Minor
Origin: Minor: nuchal ligament and spinous processes of C7 and T1 vertebrae; Major: spinous processes of T2 - T5 vertebrae
Insertion: Medial border of scapula from level of spine to inferior angle
Action: Retract scapula and rotate it to depress glenoid cavity; fix scapula to thoracic wall
Innervation: Dorsal scapular nerve (C4 and C5)
Arterial Supply: Dorsal scapular artery
Palmaris Longus
Origin: Medial epicondyle of humerus
Insertion: Distal half of flexor retinaculum and palmar aponeurosis
Action: Flexes hand (at wrist) and tightens palmar aponeurosis
Innervation: Median nerve (C7 and C8)
Arterial Supply: Ulnar artery
Flexor Pollicis Brevis
Origin: Flexor retinaculum and tubercles of scaphoid and trapezium
Insertion: Lateral side of base of proximal phalanx of thumb
Action: Flexes thumb
Innervation: Recurrent branch of median nerve (C8 and T1)
Arterial Supply: Superficial palmar branch of the radial artery
Infraspinatus
Origin: Infraspinous fossa of scapula
Insertion: Middle facet on greater tuberosity of humerus
Action: Laterally rotate arm; helps to hold humeral head in glenoid cavity of scapula
Innervation: Suprascapular nerve (C5 and C6)
Arterial Supply: Suprascapular and circumflex scapular arteries
Adductor Pollicis
Origin: Oblique head: bases of 2nd and 3rd metacarpals, capitate, and adjacent carpals; Transverse head: anterior surface of body of 3rd metacarpal
Insertion: Medial side of base of proximal phalanx of thumb
Action: Draws 1st metacarpal laterally to oppose thumb toward center of palm and rotates it medially
Innervation: Deep branch of ulnar nerve (C8 and T1)
Arterial Supply: Deep palmar arterial arch
Flexor Pollicis Longus
Origin: Anterior surface of radius and adjacent interosseous membrane
Insertion: Base of distal phalanx of thumb
Action: Flexes phalanges of 1st digit (thumb)
Innervation: Anterior interosseous nerve from median nerve (C8 and T1)
Arterial Supply: Anterior interosseous artery
Palmar Interosseous Muscles
Origin: Palmar 1 - 3: Palmar surfaces of 2nd, 4th and 5th metacarpals (unipennate muscles)
Insertion: Palmar 1 - 3: Extensor expansions of digits and bases of proximal phalanges of digits 2, 4 and 5
Action: Palmar 1 - 3: Adduct digits toward axial line and assist lumbricals in flexing metacarpophalangeal joints and extending interphalangeal joints
Innervation: Deep branch of ulnar nerve (C8 and T1)
Arterial Supply: Palmar 1 - 3: Palmar metacarpal arteries
Levator Scapulae
Origin: Posterior tubercles of transverse processes of C1 - C4 vertebrae
Insertion: Superior part of medial border of scapula
Action: Elevates scapula and tilts its glenoid cavity inferiorly by rotating scapula
Innervation: Dorsal scapular (C5) and cervical (C3 and C4) nerves
Arterial Supply: Dorsal scapular artery
Extensor Indicis
Origin: Posterior surface of ulna and interosseous membrane
Insertion: Extensor expansion of 2nd digit
Action: Extends 2nd digit and helps to extend hand
Innervation: Posterior interosseous nerve (C7 and C8), the continuation of the deep branch of the radial nerve
Arterial Supply: Posterior interosseous artery
Supinator
Origin: Lateral epicondyle of humerus, radial collateral and annular ligaments, supinator fossa and crest of ulna
Insertion: Lateral, posterior and anterior surfaces of proximal 1/3 of radius
Action: Supinates forearm (i.e., rotates radius to turn palm anteriorly)
Innervation: Deep branch of radial nerve (C5 and C6)
Arterial Supply: Recurrent interosseous artery
Flexor Digiti Minimi Brevis
Origin: Hook of hamate and flexor retinaculum
Insertion: Medial side of base of proximal phalanx of little finger
Action: Flexes proximal phalanx of little (5th) finger
Innervation: Deep branch of ulnar nerve (C8 and T1)
Arterial Supply: Ulnar artery
Extensor Carpi Radialis Longus
Origin: Lateral supracondyle ridge of humerus
Insertion: Base of 2nd metacarpal
Action: Extend and abduct hand at wrist joint
Innervation: Radial nerve (C6 and C7)
Arterial Supply: Radial artery
Extensor Carpi Ulnaris
Origin: Lateral epicondyle of humerus and posterior border of ulna
Insertion: Base of 5th metacarpal
Action: Extends and adducts hand at wrist joint
Innervation: Posterior interosseous nerve (C7 and C8), the continuation of the deep branch of the radial nerve
Arterial Supply: Ulnar artery
Flexor Digitorum Profundus
Origin: Proximal 3/4 of medial and anterior surfaces of ulna and interosseous membrane
Insertion: Base of the distal phalanx of digits 2 - 5
Action: Flexes distal phalanges at distal interphalangeal joints of medial four digits; assists with flexion of hand
Innervation: Medial part: ulnar nerve (C8 and T1); Lateral part: anterior interosseous branch of median nerve (C8 and T1)
Arterial Supply: Ulnar and anterior interosseous arteries
Anconeus
Origin: Lateral epicondyle of humerus
Insertion: Lateral surface of olecranon and superior part of posterior surface of ulna
Action: Assists triceps in extending forearm; stabilizes elbow joint; abducts ulna during pronation
Innervation: Radial nerve (C7, C8 and T1)
Arterial Supply: Middle collateral branch of deep brachial artery; Recurrent interosseous artery
Biceps Brachii
Origin: Short head: tip of coracoid process of scapula; Long head: supraglenoid tubercle of scapula
Insertion: Tuberosity of radius and fascia of forearm via bicipital aponeurosis
Action: Supinates forearm and, when it is supine, flexes forearm
Innervation: Musculocutaneous nerve (C5 and C6 )
Arterial Supply: Muscular branches of brachial artery
Supraspinatus
Origin: Supraspinous fossa of scapula
Insertion: Superior facet on greater tuberosity of humerus
Action: Initiates and assists deltoid in abduction of arm and acts with other rotator cuff muscles
Innervation: Suprascapular nerve (C4, C5 and C6)
Arterial Supply: Suprascapular artery
Extensor Digiti Minimi
Origin: Lateral epicondyle of humerus
Insertion: Extensor expansion of 5th digit
Action: Extends 5th digit at metacarpophalangeal and interphalangeal joints
Innervation: Posterior interosseous nerve (C7 and C8), the continuation of the deep branch of the radial nerve
Arterial Supply: Interosseous recurrent artery
