Upper Limb - Muscles

Question 1

Pectoralis minor

Answer 1

Origin - 3rd-5th ribs near their costal cartilages
Insertion - coracoid process of scapula
Innervation - medial pectoral nerve
Action - depresses the shoulder

Question 2

Serratus anterior

Answer 2

Origin - lateral parts of ribs 1-8
Insertion - anterior surface of the medial surface of the scapula
Innervation - long thoracic nerve
Action - protracts the scapula and holds it against thoracic wall. Rotates scapula allowing arm to be raised above 90 degrees.

Question 3

Pectoralis major

Answer 3

Origin - clavicle (clavicular head). Sternum and ribs (sternocostal head)
Insertion - intertubercular groove of humerus
Innervation - medial and lateral pectoral nerves
Action - adduct and medically rotate the humerus. Clavicular head can perform flexion.

Question 4

Biceps brachii

Answer 4

Origin - supraglenoid tubercle (long head) and coracoid process (short head) of the scapula.
Insertion - radial tuberosity
Innervation - musculocutaneous nerve
Action - supination of the forearm (main), flexion of elbow and flexion of shoulder.

Question 5

Brachialis

Answer 5

Origin - Distal half of anterior surface of humerus
Insertion - coronoid process and tuberosity of ulna
Innervation - musculocutaneous nerve and small lateral portion is radial nerve
Action - main flexor at the elbow

Question 6

Coracobrachialis

Answer 6

Origin - Coracoid process of scapula
Insertion - medial surface of the humerus at the level of the deltoid tuberosity
Innervation - musculocutaneous nerve
Action - flexion at the shoulder, resists dislocation of shoulder

Question 7

Triceps brachii

Answer 7

Origin - infraglenoid tubercule of scapula (long head), posterior surface of humerus inferior to radial groove (medial head) and posterior surface of humerus superior to radial groove (lateral head)
Insertion - olecranon of ulna
Innervation - radial nerve
Action - chief extension of forearm. Long head resist dislocation of humerus during adduction

Question 8

Anconeus

Answer 8

Origin - lateral epicondyle of the humerus
Insertion - lateral surface of the olecranon
Innervation - radial nerve
Action - moves the ulna during pronation and extends the elbow joint

Question 9

Supraspinatus

Answer 9

Origin - supraspinous fossa of the scapula
Insertion - greater tuberosity of the humerus
Innervation - Suprascapular nerve
Action - adducts the arm 0-15 degrees then assists the deltoid 15-90 degrees

Question 10

Infraspinatus

Answer 10

Origin - infraspinous fossa of the scapula
Insertion - greater tubercule of the humerus
Innervation - Suprascapular nerve
Action - laterally rotates the arm

Question 11

Subscapularis

Answer 11

Origin - subscapular fossa of scapula
Insertion - lesser tubercule of the humerus
Innervation - upper and lower subscapular nerves
Action - medially rotates the arm

Question 12

Teres minor

Answer 12

Origin - middle part of lateral border of scapula
Insertion - greater tubercule of the humerus
Innervation - axillary nerve
Action - laterally rotates the arm

Question 13

Deltoid

Answer 13

Origin - lateral third of clavicle, acromion and spine of scapula
Insertion - deltoid tuberosity of the humerus
Innervation - axillary nerve
Action - anterior part flexes arm, middle part abducts arm and posterior part extends arm.

Question 14

Teres major

Answer 14

Origin - posterior surface of the interior angle of the scapula
Insertion - Intertubercular groove of humerus
Innervation - lower subscapular nerve
Action - adducts and medially rotates the arm

Question 15

Trapezius

Answer 15

Origin - external occipital protuberance of skull, nuchal ligament and spinous processes of C7-T12 vertebrae
Insertion - lateral third of clavicle, acromion and spine of scapula
Innervation - accessory nerve
Action - superior part elevates scapula, middle part retracts scapula, inferior part depresses scapula. Superior and inferior parts work together to rotate the scapula, elevating the glenoid cavity.

Question 16

Trapezius

Answer 16

Origin - external occipital protuberance of skull, nuchal ligament and spinous processes of C7-T12 vertebrae
Insertion - lateral third of clavicle, acromion and spine of scapula
Innervation - accessory nerve
Action - superior part elevates scapula, middle part retracts scapula, inferior part depresses scapula. Superior and inferior parts work together to rotate the scapula, elevating the glenoid cavity.

Question 17

Latissimus dorsi

Answer 17

Origin - spinous process of T7-12 vertebra, iliac crest, thoraco-lumbar fascia and inferior 3 ribs.
Insertion - floor of Intertubercular groove of humerus
Innervation - thoracodorsal nerve
Action - extends, adducts and medially rotates the arm

Question 18

Levator scapulae

Answer 18

Origin - transverse processes of C1-4 vertebrae
Insertion - superior part of the medial border of the scapula
Innervation - dorsal scapula nerve
Action - elevates scapula and rotates the glenohumeral cavity inferiorly.

Question 19

Rhomboid minor

Answer 19

Origin - spinous processes of C7 & T1 vertebrae
Insertion - medial border of the scapula, at the level of the spine
Innervation - dorsal scapula nerve
Action - retract and rotate scapula, depressing the glenoid cavity

Question 20

Rhomboid major

Answer 20

Origin - spinous processes of T2-5 vertebrae
Insertion - medial border of scapula, inferior to spine
Innervation - dorsal scapula nerve
Action - retract and rotate scapula, depressing the glenoid cavity

Question 21

Pronator teres

Answer 21

Origin - medial epicondyle and coronoid process of ulna (two heads)
Insertion - lateral side of shaft of radius
Innervation - median nerve
Action - pronation

Question 22

Flexor carpi radialis

Answer 22

Origin - medial epicondyle
Insertion - base of 2nd and 3rd metacarpals
Innervation - median nerve
Action - flexion and abduction at the wrist

Question 23

Palmaris longus

Answer 23

Origin - medial epicondyle
Insertion - flexor retinaculum and palmar aponeurosis
Innervation - median nerve
Action - flexion at the wrist

Question 24

Flexor carpi ulnaris

Answer 24

Origin - medial epicondyle and along the ulna
Insertion - pisiform, hook of hamate and 5th metacarpal
Innervation - ulnar nerve
Action - flexion and adduction of the wrist

Question 25

Flexor digitorum superficialis

Answer 25

Origin - medial epicondyle and radius (two heads) Insertion - shaft of middle phalanges of the 4 fingers Innervation - median nerve Action - flexion at the MCP joints, PIP joints and wrist

Question 26

Flexor digitorum profundus

Answer 26

Origin - ulna and interosseous membrane Insertion - bases of the distal phalanges of the 4 fingers Innervation - medial half (4th and 5th digits) is ulnar nerve. Lateral half is median nerve. Action - flexes at the distal interphalangeal joints, as well as the PIPJ, MCPJ and the wrist.

Question 27

Flexor pollicis longus

Answer 27

Origin - anterior surface of radius and interosseous membrane Insertion - base of the distal phalanx of the thumb Innervation - median nerve Action - flexion at the IP and MCP joint of the thumb

Question 28

Pronator quadratus

Answer 28

Origin - anterior surface of the distal ulna Insertion - anterior surface of the distal radius Innervation - median nerve Action - primates the forearm

Question 29

Brachioradialis

Answer 29

Origin - proximal aspect of the supra-epicondylar ridge of the humerus Insertion - lateral surface of distal end of radius Innervation - radial nerve Action - flexion at the elbow - strongest when forearm is half pronated

Question 30

Extensor carpi radialis longus

Answer 30

Origin - supra-epicondylar ridge of humerus Insertion - dorsal aspect of base of metacarpal 2 Innervation - radial nerve Action - extension and abduction at the wrist

Question 31

Extensor carpi radialis brevis

Answer 31

Origin - lateral epicondyle of the humerus Insertion - dorsal aspect of base of 3rd metacarpal Innervation - deep branch of radial nerve Action - extension and abduction at the wrist

Question 32

Extensor digitorum

Answer 32

Origin - lateral epicondyle of the humerus Insertion - extensor expansions of medial four digits Innervation - deep branch of radial nerve Action - extension at the MCP and IP joints of the medial 4 fingers

Question 33

Extensor digiti minimi

Answer 33

Origin - lateral epicondyle of the humerus Insertion - extensor expansion of 5th digit Innervation - deep branch of radial nerve Action - extension at the MCP and IP joint of 5th digit

Question 34

Extensor carpi ulnaris

Answer 34

Origin - lateral epicondyle of the humerus Insertion - dorsal aspect of the base of the 5th metacarpal bone Innervation - deep branch of radial nerve Action - extension and adduction at the wrist

Question 35

Supinator

Answer 35

Origin - lateral epicondyle of the humerus and posterior surface of the ulna (two heads) Insertion - lateral surface of proximal radius Innervation - deep branch of radial nerve Action - supinate the forearm

Question 36

Abductor pollicis longus

Answer 36

Origin - interosseous membrane and adjacent posterior surfaces of the radius and ulna Insertion - lateral side of the base of the first metacarpal Innervation - posterior interosseous nerve, continuation of deep branch of radial nerve Action - abduction of the thumb

Question 37

Extensor pollicis brevis

Answer 37

Origin - interosseous membrane and posterior surface of the distal radius Insertion - dorsal aspect of base of proximal phalanx of thumb Innervation - posterior interosseous nerve, continuation of deep branch of radial nerve Action - extends at the metacarpophalangeal and carpometacarpal joints of the thumb

Question 38

Extensor pollicis longus

Answer 38

Origin - posterior surface of the ulna and interosseous membrane Insertion - distal phalanx of the thumb Innervation - posterior interosseous nerve, continuation of the deep radial nerve Action - extends all the joints of the thumb

Question 39

Extensor indicis

Answer 39

Origin - posterior surface of the ulna and interosseous membrane, distal to extensor pollicis longus Insertion - extensor expansion of 2nd digit Innervation - posterior interosseous nerve, continuation of deep branch of radial nerve Action - extends the index finger

Question 40

Opponens pollicis

Answer 40

Origin - flexor retinaculum and tubercule of the trapezium Insertion - lateral side of 1st metacarpal Innervation - recurrent branch of the median nerve Action - opposes thumb by medially rotating and flying the metacarpal on the trapezium.

Question 41

Abductor pollicis brevis

Answer 41

Origin - flexor retinaculum and tubercules of the scaphoid and trapezium Insertion - lateral side of the proximal phalanx Innervation - recurrent branch of the median nerve Action - abducts the thumb

Question 42

Flexor pollicis brevis

Answer 42

Origin - flexor retinaculum and tubercule of the trapezium Insertion - base of the proximal phalanx of the thumb Innervation - recurrent branch of the median nerve Action - flexes the thumb at the MCP and CMC joints

Question 43

Opponens digiti minimi

Answer 43

Origin - hook of hamate and flexor retinaculum Insertion - medial border of 5th metacarpal Innervation - deep branch of ulnar nerve Action - rotates the 5th metacarpal towards the palm, producing opposition

Question 44

Abductor digiti minimi

Answer 44

Origin - pisiform Insertion - medial side of base of the proximal phalanx of the little finger Innervation - deep branch of ulnar nerve Action - abducts 5th digit

Question 45

Flexor digiti minimi brevis

Answer 45

Origin - hook of hamate and flexor retinaculum Insertion - medial side of base of the proximal phalanx of the 5th finger Innervation - deep branch of the ulnar nerve Action - flexion at the MCP and CMC joints.

Question 46

1st and 2nd lumbricals

Answer 46

Origin - lateral two tendons of flexor digitorum profundus, as uni pennate muscles Insertion - lateral sides of extensor expansions of the 2nd and 3rd digits Innervation - median nerve Action - flex MCP and extend IP joints

Question 47

3rd and 4th lumbricals

Answer 47

Origin - medial 3 tendons of the flexor digitorum profundus, as bipennate muscles Insertion - lateral sides of extensor expansions of the 3rd and 4th digits Innervation - deep branch of the ulnar nerve Action - flexs MCP and extends at the IP joints

Question 48

Dorsal interossei

Answer 48

Origin - adjacent sides of two metacarpals, as bipennate muscles Insertion - bases of the proximal phalanges and extensor expansions of 2nd-4th digits Innervation - deep branch of ulnar nerve Action - abduct 2nd-4th digits from axial line (DAb)and assist lumbricals

Question 49

Palmar interossei

Answer 49

Origin - palmar surface of 2nd, 4th and 5th metacarpals, as uni pennate muscles Insertion - extensor expansion and base of proximal phalanx of same finger Innervation - deep branch of ulnar nerve Action - adduct 2nd, 4th and 5th digits towards the axial line (PAd) and assist lumbricals

Question 50

Adductor pollicis

Answer 50

Origin - capitate and metacarpals II and III (oblique head). Anterior surface of shaft of 3rd metacarpal (transverse head) Insertion - medial side of base of proximal phalanx of thumb Innervation - deep branch of ulnar nerve Action - adducts thumb

Question 51

Palmaris brevis

Answer 51

Origin - medial border of palmar aponeurosis Insertion - skin of medial border of the hand Innervation - ulnar nerve Action - wrinkles the skin of the hypothenar eminence and deepens the curvature of the hand, improving grip