Muscles of the Wrist

Question 1

Extensor Carpi Radialis Longus

Answer 1

Extend the wrist (radiocarpal joint); Abduct (radially deviate) the wrist (radiocarpal joint); Assist to flex the elbow (humeroulnar joint)

Practical Examples:

• Stabilizing the wrist while gripping (opening a jar)
• Washing the dishes
• Turning off a faucet

Question 2

Extensor Carpi Radials Brevis

Answer 2

Extend the wrist (radiocarpal joint); Abduct (radially deviate) the wrist (radiocarpal joint); Assist to flex the elbow (humeroulnar joint)

Practical Examples:

• Stabilizing the wrist while gripping (opening a jar)
• Washing the dishes
• Turning off a faucet

Question 3

Wad of three

Answer 3

Brachioradialis, Extensor Cari Radialis Longus, and Extensor Carpi Radialis Brevis – extends distally from the lateral supracondylar ridge of the humerus

Question 4

Extensor Carpi Ulnaris

Answer 4

Extend the wrist (radiocarpal joint); Adduct (ulnar deviation) the wrist (radiocarpal joint)

Practical Examples:

• Shaping soft clay for an art project
• Pulling a book off a tall library shelf
• Reaching into the backseat of your car

Question 5

Extensor Digitorum

Answer 5

Extend the second through fifth fingers (metacarpophalangeal and interphalangeal joints); assist to extend the wrist (radiocarpal joint

Practical Examples:

• Playing the piano or trumpet
• Holding your hand up to give the Vulcan hand greeting
• Releasing a handshake

Question 6

Extensor Indicis

Answer 6

Located deep to the extensor digitorum and extensor carpi ulnaris, this small but crucial muscle assists in extending the index finger

• Extend the second finger (metacarpophalangeal joint); Adduct the second finger; assist to extend the wrist (radiocarpal joint)

Question 7

Flexor Carpi Radialis (Superficial layer)

Answer 7

Flex the wrist (radiocarpal joint); Abduct (radial deviation) the wrist (radiocarpal joint); assist to flex the elbow (humeroulnar joint)

Practical Examples:

• Squeezing the hand strap of a fast-moving train
• Turning a water valve
• Holding a cell phone
• Resisting flexion at the wrist often brings the tendon to the surface
• Is only 60% as strong as FCU

Question 8

Flexor Carpi Ulnaris (superficial layer)

Answer 8

Flex the wrist (radiocarpal joint); Adduct (ulnar deviation) the wrist (radiocarpal joint); assist to flex the elbow (humeroulnar joint)

Practical Examples:

• Using your hand to brush food off a kitchen table
• Unscrewing a tight lid on a jar
• Delivering an incredible judo chop
• Using a hammer or stroking an axe

Question 9

Palmaris Longus (superficial layer)

Answer 9

Tense the palmar fascia; flex the wrist (radiocarpal joint); assist to flex the elbow (humeroulnar joint)

Practical Examples:

• Palming a large grapefruit
• Doing a fingertip push-up
• Making a snowball

Question 10

Flexor Digitorum Superficialis

Answer 10

Flex the second through fifth fingers (metacarpophalangeal and proximal interphalangeal joints); Flex the wrist (radiocarpal joint)

Practical examples:

• Picking up small objects such as crumbs, needles, or coins
• Playing guitar
• Typing a letter
• Tying your shoelaces
• Buttoning your shirt

Tightness in this muscle can result in a claw hand deformity

Question 11

Flexor Digitorum Profundus

Answer 11

Flex the second through fifth fingers (metacarpophalangeal and distal interphalangeal joints); assist to Flex the wrist (radiocarpal joint)

Practical examples:

• Picking up small objects such as crumbs, needles, or coins
• Playing guitar
• Typing a letter
• Tying your shoelaces
• Buttoning your shirt