Upper limb 2: Elbow and forearm

Question 1

What would a mid-shaft fracture of the the spiral groove of the humerus result in?

Answer 1

Radial n and profunda a. damage

Question 2

What nerve passes posterior to the medial epicondyle?

Answer 2

Ulnar n

Question 3

What muscle attaches to the radial tuberosity?

Answer 3

Biceps bracii

Question 4

What attaches to the coronoid process of the ulna?

Answer 4

Brachialis muscle

Question 5

Why are there raised ridges of bone on the shafts of the radius and ulna?

Answer 5

Attachment of the interosseous membrane - allows displacement of forces

Question 6

What can potentially be damaged if there is a fracture to the neck of the radius bone?

Answer 6

Posterior interosseous n.

Question 7

Does the lateral collateral ligament resists varus or vlagus stress?

Answer 7

Varus (where is my pig)

Question 8

What are the landmarks of the anconeus triangle? (Used for elbow aspiration/injection)

Answer 8

Radial head
Olecranon
Lateral epicondyle

Question 9

How many radioulnar joints are there and what movements do they permit?

Answer 9

2 radiounlar joints (proximal and distal) - permit pronation and supination
Synovial pivot joint

Question 10

What muscle bring about the pronation/supination movement and what is the stronger? Name the nerves invovled.

Answer 10

Supination is stronger
Supination: Biceps brachii (musculocutaneous n) and supinator (radial n)
Pronation: Pronator teres and pronator quadratus (median n)

Question 11

What is the condition called when swinging on a child’s arm can pull the annular ligament and thus the joint is dislocated?

Answer 11

Nursemaid’s elbow

Question 12

What is the golden rule of the anterior compartment of the forearm?

Answer 12

Everything is median nerve except 1.5 muscles:
Flexor carpi ulnaris (ulnar n)
Half of flexor digitorum profundus (half is ulnar n)

Question 13

What is the condition called when the medial epicondyle of the elbow is inflammed?

Answer 13

Golfer’s elbow

Question 14

What ligament forms the roof of the carpal tunnel?

Answer 14

Transverse carpal ligament

Question 15

How can you test if JUST the Flexor digitorum profundus muscle is working (precise)? What other test exists to test the FDP but is not as precise?

Answer 15

Precise: hold the patient’s finger ask them to flex their DIP joints. Digits 2&3 - median n; digits 4&5 - ulnar n.
Not precise: Grip test (ask patient to grip your fingers) Tests FDP and FDSuperficialis

Question 16

Is it true that the tendons of FDP pass through those of FDS?

Answer 16

yes as they need to get to the DIP joints.

Question 17

What can cause inflammation of the lateral epicondyle of the elbow?

Answer 17

Tennis backhand

Question 18

What happens if extensor and flexor carpi ulnaris contract together?

Answer 18

Wrist adduction

Question 19

What is the innervation of the posterior forearm?

Answer 19

Radial n or its branch posterior interosseous n

Question 20

How many extensor compartments of the wrist are there?

Answer 20

6 - covered in common synovial sheaths

Question 21

What happens if compartment 1 of the extensor compartments of the wrist are affected? E.g. due to overuse/painful

Answer 21

De-Quervains tenosynovitis (‘mommy’s thumb’/’blackberry’/’gaming’) - Extensor Pollicis Brevis
Thumb is extended and abducted

Question 22

How can compartment 6 (extensor carpi ulnaris) be damaged?

Answer 22

ECU can wear on the ulnar styloid process and rupture

Question 23

How can compartment 3 (extensor pollicis longus) be damaged?

Answer 23

EPL can wear on the dorsal radial tubercle and rupture

Question 24

What is special about the brachioradialis muscle?

Beer Raising

Answer 24

Is a flexor muscle but is in the posterior compartment of the arm. Flexes elbow and moves forearm to mid-pronation/supination position.
Radial n

Question 25

What are the borders of the cubital fossa?

Answer 25

Brachioradialis (lateral)
Interepicondylar line (superior)
Pronator teres (medial)

Question 26

What is located within the cubital fossa? (TAN)

Answer 26

Biceps tendon (lateral)
Brachial artery 
Medial n (medial)

Question 27

How do the median and ulnar nerves enters the hand?

Answer 27

Median n - carpal tunnel

Ulnar n - Guyon’s canal

Question 28

What would happen to the hand if the radial a. was blocked just proximal to the wrist?

Answer 28

Nothing, superficial parlmar arch would pick up the slack. The hand has a collateral blood supply (deep palmar arch).

Question 29

Where does the ulnar a. sit in relation to the flexor carpi ulnaris?

Answer 29

Under or lateral to it on the anterior wrist