Elbow + Forearm

Question 1

What is at risk of damage with a humeral mid-shaft fracture?

Answer 1

Can damage radial nerve and profunda brachii artery if fracture is through the spiral groove (located at posterior aspect of humerus)

Question 2

Which nerve passes posteriorly to the medial epicondyle of the humerus?

Answer 2

Ulnar nerve

Question 3

What can cause a fracture of the olecranon?

Answer 3

Direct trauma

Avulsion caused by a strong triceps contraction (e.g. in a fall)

Question 4

Which nerve may be affected by a fractured neck of radius?

Answer 4

Posterior interosseous nerve (branch of radial nerve)

Question 5

What movement does the LCL of the elbow resist?

Answer 5

Adduction/ varus movement of forearm

Question 6

What movement does the MCL of the elbow resist?

Answer 6

Abduction/ valgus movement of forearm

Question 7

What are the markers of the anconeus triangle?

Answer 7

Radial head, lateral epicondyle of humerus and olecranon of ulna

Question 8

What is the Anconeus triangle used for?

Answer 8

Region for elbow injection or aspiration

Question 9

What movements does the radioulnar joint permit?

Answer 9

Pronation

Supination

Question 10

What muscles are involved in supination of the forearm?

Answer 10

Biceps Brachii (innervated by musculocutaneous C5+C6) 
Supinator (Layer 2 of posterior forearm; innervated by posterior interosseous, branch of radial C5+C6)

Question 11

What muscles are involved in pronation of the forearm?

Answer 11

Pronator Teres (Layer 1 of anterior forearm - innervated by median C6+C7) 
Pronator Quadratus (Layer 3 of anterior forearm - innervated by anterior interosseous, branch of median)

Question 12

What forms the proximal (or superior) radioulnar joint?

Answer 12

Radius, Ulna and Annular ligament

Question 13

What type of joint are the radioulnar joints?

Answer 13

Synovial pivot joints

Question 14

What does the articular disc of the wrist do?

Answer 14

Separates ulna from proximal carpal bones of wrist joint (radiocarpal joint)

Question 15

What actions do the anterior compartment of the forearm muscles do?

Answer 15

Wrist flexion
Digit flexion
Pronation

Question 16

What actions do the posterior compartment of the forearm muscles do?

Answer 16

Wrist extension
Digit extension
Supination
Thumb abduction

Question 17

Which muscles are involved in flexion of the wrist?

Answer 17

Anterior compartment of forearm:
Flexor Carpi Ulnaris (ulnar nerve)
Flexor Carpi Radialis (median nerve)
Palmaris Longus (median nerve)

Question 18

What muscle abducts the wrist?

Answer 18

Flexor Carpi Radialis (median nerve)

Question 19

What muscle adducts the wrist?

Answer 19

Flexor Carpi Ulnaris (ulnar nerve)

Question 20

What are the attachment points for anterior compartment muscles?

Answer 20

Tendons of layers 1 + 2 attach to medial epicondyle of humerus

Question 21

What is Golfer’s Elbow?

Answer 21

Medial epicondylitis

Question 22

What is Tennis Elbow?

Answer 22

Lateral epicondylitis

Question 23

What forms the roof of the carpal tunnel?

Answer 23

Transverse carpal ligament

Question 24

What muscles flex the fingers?

Answer 24

Layer 2 anterior compartment: Flexor Digitorum Superficialis (up to proximal interphalangeal joints)
Layer 3 anterior compartment: Flexor Digitorum Profundus (to the distal interphalangeal joints)

Question 25

What nerves cause finger flexion?

Answer 25

Flexor Digitorum Superficialis (to digits 2-5) + Flexor Digitorum Profundus (to digits 2+3) innervated by the median nerve Flexor Digitorum Profundus (to digits 4+5) innervated by the ulnar nerve [Nb. Need to test finger flexion at DIP of 2/3 and 4/5 to test for median and ulnar nerve function]

Question 26

What muscle flexes the thumb?

Answer 26

Flexor Pollicis Longus (Layer 3 of anterior forearm - innervated by median nerve)

Question 27

What is the golden rule of innervation to the anterior forearm?

Answer 27

Everything median EXCEPT flexor carpi ulnaris and flexor digitorum profundus to digits 4 and 5 which are innervated by the ulnar nerve

Question 28

What muscles extend the wrist?

Answer 28

Extensor Carpi Radialis Longus + Brevis (Layer 1 of posterior forearm - innervated by deep branch of radial nerve) Extensor Carpi Ulnaris (Layer 1 of posterior forearm - innervated by deep branch of radial nerve)

Question 29

Where is the origin of the muscles of layer 1 of posterior forearm?

Answer 29

Lateral epicondyle of humerus (except ECRL and Anconeus) | ECRL = supracondylar ridge

Question 30

What muscles abduct the wrist?

Answer 30

Extensor Carpi Radialis Longus + Brevis (Layer 1 of posterior forearm - innervated by deep branch of radial nerve)

Question 31

What muscle adducts the wrist?

Answer 31

Extensor Carpi Ulnaris (Layer 1 of posterior forearm - innervated by deep branch of radial nerve)

Question 32

What muscles extend the fingers?

Answer 32

``` Extensor Digitorum (Layer 1 of posterior forearm - innervated by deep branch of radial nerve) Extensor Digitorum Minimi (Layer 1 of posterior forearm - innervated by deep branch of radial nerve) - to 5th digit only Extensor Indicis (Layer 2 of posterior forearm - innervated by posterior interosseous, branch of radial nerve) - to PIP of index finger only ```

Question 33

What muscles extend the thumb?

Answer 33

Extensor Pollicis Brevis (Layer 2 of posterior forearm - innervated by posterior interosseus branch of radial nerve) - to MCP only Extensor Pollicis Longus (Layer 2 of posterior forearm - innervated by posterior interosseus branch of radial nerve) - to all joints

Question 34

What muscles abducts the thumb?

Answer 34

Abductor Pollicis Longus (Layer 2 of posterior forearm - innervated by posterior interosseous branch of radial nerve)

Question 35

What is affected in De Quervains Tenosynovitis?

Answer 35

Compartment 1 of wrist (containing abductor pollicis longus and extensor pollicis brevis)

Question 36

What can be affected in Compartment 3 of the wrist?

Answer 36

Extensor Pollicis Longus - can wear on the dorsal radial tubercle and rupture

Question 37

What can be affected in Compartment 6 of the wrist?

Answer 37

Extensor Carpi Ulnaris - can wear on the ulnar styloid process and rupture

Question 38

What is the contents of Compartment 2 of the wrist?

Answer 38

Extensor Carpi Radialis Longus + Brevis

Question 39

What is the contents of Compartment 4 of the wrist?

Answer 39

Extensor Digitorum | Extensor Indicis

Question 40

What is the contents of Compartment 5 of the wrist?

Answer 40

Extensor Digitorum Minimi

Question 41

What are the actions of the brachioradialis muscle?

Answer 41

Elbow flexion | Moves forearm to mid pronation/ supination

Question 42

What forms the borders of the cubital fossa?

Answer 42

``` Lateral = brachioradialis Medial = pronator teres Superior = inter-epicondylar line Roof = aponeurosis of biceps ```