Elbow, Wrist, and Hand Muscles

Question 1

Brachialis

Answer 1

O: Distal half of the humerus, anterior surface

I: Coronoid process, ulnar tuberosity

A: Elbow flexion

N: Musculocutaneous n. (C5, C6)

Question 2

Biceps Brachii

Answer 2

O: Long head–Supraglenoid tubercle of the scapula
Short head–Coracoid process of scapula

I: Radial tuberosity

A: Elbow flexion, forearm supination

N: Musculocutaneous n. (C5, C6)

Question 3

Brachioradialis

Answer 3

O: Lateral supracondylar ridge on the humerus

I: Styloid process of radius

A: Elbow flexion

N: Radial n. (C5, C6)

Question 4

Triceps

Answer 4

O:
Long head–Infraglenoid tubercle of scapula
Lateral head–Inferior to the greater tubercle on posterior humerus
Medial head–Posterior surface of humerus

I: Olecranon process of ulna

A: Elbow extension

N: Radial n. (C6, C7, C8)

Question 5

Anconeus

Answer 5

O: Lateral epicondyle of humerus

I: Lateral and inferior to olecranon process of ulna

A: Not a prime mover, but assists with elbow extension

N: Radial n. (C6, C7, C8)

Question 6

Pronator teres

Answer 6

O: Medial epicondyle of humerus and coronoid process of ulna

I: Lateral aspect of radius at midpoint

A: Forearm pronation, assists in elbow flexion

N: Median n. (C6, C7)

Question 7

Pronator Quadratus

Answer 7

O: Distal 1/4 of ulna

I: Distal 1/4 of radius

A: Forearm pronation

N: Median n. (C8, T1)

Question 8

Supinator

Answer 8

O: Lateral epicondyle of humerus and adjacent ulna

I: Anterior surface of proximal radius

A: Forearm supination

N: Radial n. (C6)

Question 9

Flexor carpi radialis

Answer 9

O: Medial epicondyle of humerus

I: Base of 2nd and 3rd metacarpals on palmar surface

A: Wrist flexion, radial deviation

N: Median n. (C6, C7)

Question 10

Palmaris longus

Answer 10

O: Medial epicondyle of humerus

I: Palmar aponeurosis of 2nd-5th metacarpals

A: Wrist flexion

N: Median n. (C6, C7)

Question 11

Flexor carpi ulnaris

Answer 11

O: Medial epicondyle of humerus, posterior aspect of proximal ulna

I: Pisiform, hamate, and base of 5th metacarpal on palmar surface

A: Wrist flexion, ulnar deviation

N: Ulnar n. (C8, T1)

Question 12

Flexor digitorum superficialis

Answer 12

O: Medial epicondyle of humerus
Ulnar head: Medial coronoid process
Radial head: Upper 2/3 of anterior border of the radius, distal to the radial tuberosity

I: Each tendon splits and attaches to the sides of the middle phalanx of the four fingers on the palmar surface

A: Flexion of the fingers at the MCP and PIP joints, wrist flexion

N: Median n. (C7, C8, T1)

Question 13

Flexor digitorum profundus

Answer 13

O: Proximal 3/4 of anterior and medial ulna

I: Base of distal phalanges of digits 2-5

A: Flexion of digits 2-5 at MCP, PIP, and DIP joints; wrist flexion

N: Median n. (C8, T1) to 2nd and 3rd digits; Ulnar n. (C8, T1) to 4th and 5th digits

Question 14

Flexor pollicis longus

Answer 14

O: Middle anterior surface of the radius, anterior medial border of the ulna distal to the coronoid process

I: Base of distal phalanx of thumb on palmar surface

A: Flexion of thumb CMC, MCP, and IP; Wrist flexion; Radial deviation

N: Median n. (C8, T1)

Question 15

Extensor carpi ulnaris

Answer 15

O: Lateral epicondyle of humerus, middle posterior border of the ulna

I: Base of 5th metacarpal on dorsal surface

A: Wrist extension, ulnar deviation

N: Radial n. (C6, C7, C8)

Question 16

Extensor carpi radialis brevis

Answer 16

O: Lateral epicondyle of humerus

I: Base of 3rd metacarpal on dorsal surface

A: Wrist extension; radial deviation

N: Radial n. (C6, C7)

Question 17

Extensor carpi radialis longus

Answer 17

O: Distal 1/3 of lateral supracondylar ridge of humerus, lateral epicondyle of humerus

I: Base of 2nd metacarpal on dorsal surface

A: Wrist extension, radial deviation

N: Radial n. (C6, C7)

Question 18

Extensor digitorum

Answer 18

O: Lateral epicondyle of humerus

I: Four tendons to bases of middle and distal phalanxes of digits 2-5

A: Extension of digits 2-5 at MCP joints

N: Radial n. (C6, C7, C8)

Question 19

Extensor indices

Answer 19

O: Middle to distal 1/3 of posterior ulna

I: Base of middle and distal phalanx of the 2nd digit on the distal surface

A: Extension of index finger at MCP joint

N: Radial n. (C6, C7, C8)

Question 20

Extensor digiti minimi

Answer 20

O: Lateral epicondyle of humerus

I: Base of middle and distal phalanx of the 5th digit on the dorsal surface

A: Extension of the little finger at the MCP joint

N: Radial n. (C6, C7, C8)

Question 21

Extensor Pollicis Brevis

Answer 21

O: Posterior surface of lower middle radius

I: Base of proximal phalanx of thumb on dorsal surface

A: Extension of the thumb at the CMC and MCP joints; radial deviation; weak wrist extension

N: Radial n. (C6, C7, C8)

Question 22

Abductor pollicis longus

Answer 22

O: Posterior aspect of radius and midshaft of ulna

I: Base of 1st metacarpal on the dorsal lateral surface

A: Abduction of the thumb at the CMC joint, radial deviation, extension of thumb at CMC joint

N: Radial n. (C6, C7)