Wrist & Hand: Action, Origin, Insertion, & Nerve Innervation

Question 1

Flexor carpi radialis

Answer 1

Action: Flex and radially deviate the wrist
May assist to flex the elbow

Origin: Common flexor tendon from medial epicondyle of humerus

Insertion: Bases of 2nd and 3rd metacarpals

Nerve Innervation: Median C6 to C8

Question 2

Flexor carpi ulnaris

Answer 2

Action: Flex and ulnarly deviate the wrist
Assit to flex the elbow

Origin: (Humeral head) Common flexor tendon from medial epicondyle of humerus
(ulnar head) Posterior surface of proximal two-thirds of ulna

Insertion: Pisiform, hook of hamate, and base of 5th metacarpal

Nerve Innervation: Ulnar C7 and C8, T1

Question 3

Palmaris longus

Answer 3

Action: Tense the palmar fascia
Flex the wrist
May assist to flex the elbow

Origin: Common flexor tendon from medial epicondyle of humerus

Insertion: Flexor retinaculum and palmar aponeurosis

Nerve Innervation: Median C6 to C8, T1

Question 4

Flexor digitorum superficialis

Answer 4

Action: Flex the 2nd through 5th fingers
and flex the wrist

Origin: Common flexor tendon from medial epicondyle of humerus, ulnar collateral ligament, coronoid process of ulna, interosseous membrane, and proximal shaft radius

Insertion: Sides of middle phalanges of 2nd through 5th fingers

Nerve Innervation: Median C7 and C8, T1

Question 5

Flexor digitorum profundus

Answer 5

Action: Flex the 2nd through 5th fingers
Assist to flex wrist

Origin: Anterior and medial surfaces of proximal three-quarters of ulna

Insertion: Bases of distal phalanges, volar surface of 2nd through 5th fingers

N: 2nd and 3rd fingers: Median C7 and C8, T1
4th and 5th fingers: Ulnar C7 and C8, T1

Question 6

Flexor pollicis longus

Answer 6

Action: Flex the thumb
Assist to flex the wrist

Origin: Anterior surface of radius and interosseous membrane

Insertion: Base of distal phalanx of thumb

Nerve Innervation: Median C6 to C8, T1

Question 7

Extensor Carpi Radialis Longus and Brevis

Answer 7

Action: Extend the wrist
Radially deviate the wrist
Assist to flex the elbow

Origin: (Longus) Distal one-third of the lateral supercondylar ridge of humerus
(Brevis) Common extensor tendon from the lateral epicondyle of humerus

Insertion: (Longus) Base of 2nd metacarpal
(Brevis) Base of 3rd metacarpal

Nerve Innervation: (Longus) Radial C5 to C8
(Brevis) Radial C6 to C8)

Question 8

Extensor Carpi Ulnaris

Answer 8

Action: Extend the wrist
Ulnarly deviate the wrist

Origin: Common extensor tendon from the lateral epicondyle of humerus

Insertion: Base of 5th metacarpal

Nerven Innervation:Radial C6 to C8

Question 9

Extensor digitorum

Answer 9

Action: Extend the 2nd through 5th fingers
Assist to extend the wrist

Origin: Common extensor tendon from the lateral epicondyle of humerus

Insertion: Bases of middle and distal phalanges of 2nd through 5th fingers

Nerve Innervation: Radial C6 to C8

Question 10

Extensor Indicis

Answer 10

Action: Extend the 2nd finger
Adduct the 2nd finger
May assist to extend the wrist

Origin: Posterior surface of distal shaft of ulna and interosseous membrane

Insertion: Tendon of the extensor digitorum at the level of the 2nd metacarpal

Nerve Innervation: Radial C6 to C8

Question 11

Abductor pollicis longus

Answer 11

Action: Radially abduct the thumb
Extend the thumb
Radially deviate the wrist

Origin: Posterior surface of the radius and ulna, and interosseous membrane

Insertion: Base of 1st metacarpal

Nerve Innervation: Radial C6 to C8

Question 12

Extensor pollicis longus and brevis

Answer 12

Action: Extend the thumb, EPL only
Extend the thumb
Radially deviate the wrist

Origin: (Longus) Posterior surface of ulna and interosseous membrane
(Brevis) Posterior surface of radius and interosseous membrane

Insertion: (Longus) Base of distal phalanx of thumb
(Brevis) Base of proximal phalanx of thumb

Nerve Innervation: Radial C6 to C8

Question 13

Abductor pollicis brevis

Answer 13

Action: Abduct the thumb
Assist in opposition of the thumb

Origin: Flexor retinaculum, trapezium, and scaphoid tubercles

Insertion: Base of proximal phalanx of thumb

Nerve Innervation: Median C6 to C8, T1

Question 14

Flexor pollicis brevis

Answer 14

Action: Flex the thumb
Assist in opposition of the thumb

Origin: (Superficial head) Flexor retinaculum
(Deep head) Trapezium, trapezoid, and capitate

Insertion: Base of proximal phalanx of thumb

Nerve Innervation: (Superficial head) Median to C6 to C8, T1
(Deep head) Ulnar C8 and T1

Question 15

Opponens pollicis

Answer 15

Action: Opposition of thumb at the carpometacarpal joint (bringing the pads of the thumb and 5th finger together)

Origin: Flexor retinaculum and tubercle of the trapezium

Insertion: Entire length of 1st metacarpal bone, radial surface

Nerve Innervation: Median C6 to C8, T1

Question 16

Abductor digiti minimi

Answer 16

Action: Abduct the 5th finger
Assist in opposition of the 5th finger toward the thumb

Origin: Pisiform and tendon of flexor carpi ulnaris

Insertion: Base of proximal phalanx of 5th finger, ulnar surface

Nerve Innervation: Ulnar C7 and C8, T1

Question 17

Flexor digiti minimi

Answer 17

Action: Flex the 5th finger
Assist in opposition of the 5th finger toward the thumb

Origin: Hook of hamate and flexor retinaculum

Insertion: Base of proximal phalanx of 5th finger, volar surface

Nerve Innervation: Ulnar C7 and C8, T1

Question 18

Opponens digiti minimi

Answer 18

Action: Opposition of the 5th finger at the carpometacarpal joint

Origin: Hook of hamate and flexor retinaculum

Insertion: Shaft of 5th metacarpal, ulnar surface

Nerve Innervation: Ulnar C7 and C8, T1

Question 19

Palmar interossei

Answer 19

Action: Adduct the thumb, 2nd, 4th, and 5th fingers toward the 3rd finger
Assist to flex the thumb, 2nd, 4th, and 5th fingers at the metacarpophalangeal joints
Assist to extend the thumb, 2nd, 4th, and 5th fingers at the interphalangeal joints

Origin: Base of 1st, 2nd, 4th, and 5th metacarpals

Insertion: Base of proximal phalanx of the related finger and the extensor aponeurosis

Nerve Innervation: Ulnar C8 and T1

Question 20

Dorsal interossei

Answer 20

Action: Abduct the 2nd, 3rd, and 4th fingers at the metacarpophalangeal joints
Assist to flex the 2nd, 3rd, and 4th fingers at the metacarpophalangeal joints
Assist to extend the 2nd, 3rd, and 4th fingers at the interphalangeal joints

Origin: Adjacent sides of all metacarpals

Insertion: Base of the proximal phalanx of the 2nd, 3rd, and 4th fingers and the extensor aponeurosis

Nerve Innervation: Ulnar C8 and T1

Question 21

Adductor pollicis

Answer 21

Action: Adduct the thumb
Assist to flex the thumb

Origin: Capitate, 2nd and 3rd metacarpals

Insertion: Base of proximal phalanx of thumb

Nerve Innervation: Ulnar C8 and T1

Question 22

Lumbricals (of the hand)

Answer 22

Action: Extend the 2nd through 5th fingers at the interphalangeal joints
Flex the 2nd through 5th fingers at the metacarpophalangeal joints

Origin: Surfaces of the flexor digitorum profundus

Insertion: Extensor aponeurosis on dorsal surface of phalanges

Nerve Innervation: (2nd and 3rd fingers) Median C6 to C8, T1
(4th and 5th fingers) Ulnar C7 and C8, T1