Posterior forearm

Question 1

What nerve supplies the posterior forearm?

Answer 1

-Radial

Question 2

Name the muscles of the posterior forearm

Answer 2

• 3 to the wrist -> ECRL, ECRB. and ECU
• 3 to the fingers -> ED, EDM, EI
• 3 to the thumb -> EPL, EPB, ABPL
• 3 misc -> brachioradialis, Anconeous, Supinator

Question 3

What is the function of the muscles in the posterior forearm?

Answer 3

-Extension at the wrist and fingers

Question 4

What is the function of brachioradialis?

Answer 4

-Flexion of elbow (especially in half pronated position)

Question 5

How can brachioradialis act as a landmark to find radial artery and nerve?

Answer 5

-They are sandwiched between brachioradialis and deep flexor muscles in distal forearm

Question 6

What are the functions of extensor carpi radialis longus and brevis?

Answer 6

-ABdution and extension of the wrist

Question 7

How can you tell the difference between ECRL and ECRB?

Answer 7

-ECRL is superficial and slimmer to ECRB

Question 8

What is the function of extensor digitorum?

Answer 8

-Main extensor of the fingers at MCP and both IP joints

Question 9

How do you test the function of ED?

Answer 9

• Forearm pronated

- Extend fingers against resistance

Question 10

Where does ED insert?

Answer 10

-Into the extensor hood of each finger

Question 11

Where does Extensor digiti minimi lay in relation to ED?

Answer 11

-Medially

Question 12

What is the function of extensor digiti minimi?

Answer 12

• Extends the 5th digit

- Contributes to wrist extension

Question 13

What is the function of extensor carpi ulnaris?

Answer 13

• Extension of the wrist

- ADduction

Question 14

What does anconeous blend with?

Answer 14

-Fibres of triceps brachii

Question 15

What is the function of anconeous?

Answer 15

• Moves ulna during pronation

- extension of the elbow joint

Question 16

-What is Lateral epicondylitis?

Answer 16

• Tennis elbow
• Inflammation of the periosteum of the lateral epicondyle
• Onset usually 40-50 years
• Caused by repetitive strain of suprficial extensors

Question 17

What are the superficial extensor muscles?

Answer 17

-ECRL, ECRB, ECU, ED, EDM, Brachioradialis, Anconeous

Question 18

What is the function of supinator?

Answer 18

-Supination

Question 19

What nerve passes between the two heads of supinator?

Answer 19

-Deep branch of radial nerve

Question 20

Where is ABductor pollicis longus situated in relation to supinator?

Answer 20

-Immediately distally

Question 21

What is the function of ABductor pollicis longus?

Answer 21

-ABducts the thumb

Question 22

Why is the Abductor pollicis longus tendon important?

Answer 22

-Makes the lateral border of the anatomical snuff box

Question 23

Where is extensor pollicis brevis situated in relation to ABductor pollicis longus?

Answer 23

-Deep and medial

Question 24

What is the function of Extensor pollicis brevis?

Answer 24

-Extends the carpometacaral and metacarpopalangeal joints of the thumb

Question 25

Why is the tendon of extensor pollicis brevis important?

Answer 25

-Makes the lateral border of the anatomical snuff box

Question 26

How can you tell the difference between EPB and EPL?

Answer 26

-EPL has a larger muscle belly

Question 27

What is the function of EPL?

Answer 27

-Extends all the joints of the thumb

Question 28

Why is the tendon of extensor pollicis longus important?

Answer 28

-Makes the medial border of the anatomical snuff box

Question 29

What is the function of extensor indices?

Answer 29

-Extends the index finger

Question 30

What is wrist drop?

Answer 30

-Unopposed flexion of the wrist caused by radial nerve injury that has occured proximal to the elbow

Question 31

Where and how are common sites of damage to the radial nerve?

Answer 31

• Axilla -> humeral dislocation or proximal fracture

- Radial groove -> humeral shaft fracture