Lecture 6.2

Question 1

What kind of joint is the elbow joint?

Answer 1

Compound, hinge joint; elbow and proximal radioulnar joint in the same capsule..

Question 2

Does the elbow joint have an articular disk/meniscus?

Answer 2

No

Question 3

What is the blood supply of the elbow joint?

Answer 3

Branches of the brachial artery

Question 4

What is the nerve supply of the elbow joint?

Answer 4

Musculocutaneous nerve

Radial nerve

Ulnar nerve

Question 5

What are the main stabilizing ligaments of the elbow joint?

Answer 5

Radial collateral ligament

Ulnar collateral ligament:

Question 6

Where does the ulnar collateral ligament originate and insert?

Answer 6

Goes from medial epicondyle and produces 3 bands:

Anterior: inserts onto coranoid process

Posterior: olecranon process of ulna

Oblique: coranoid and olecranon process.

Question 7

Where does the radial collateral ligament insert?

Answer 7

Radial collateral ligament blends with the annular ligament.

Question 8

What type of deviation does the forearm have?

Answer 8

Distal end of forearm deviates laterally compared to the proximal end. (valgus deviation)

Question 9

Why is the ulnar collateral ligament the main stabilizing ligament of the elbow joint?

Answer 9

The ulnar collateral ligament prevents excessive valgus deviation.

*If varus deviation was the deviation of the forearm the ligaments there would have been the main stabilizing ligaments.

Question 10

What can be found in the fossae of the olecranon, coranoid, and radial fossae to cushion the entry of their processes?

Answer 10

Olecranon, radial, and coranoid processes have fat pads.

Question 11

Where can the olecranon bursa be found? What is its function?

Answer 11

olecranon bursa is between the skin and olecranon process this prevents excessive friction at that region.

Question 12

Which muscles articulate during flexion at the elbow joint?

Answer 12

Flexion occurs mostly between humerus and the ulna.

Question 13

When does the radius contact the humerus during flexion?

Answer 13

Radius contacts humerus only at closely packed position.

Question 14

What is the closely packed position of the radius during flexion?

Answer 14

90 degrees flexion and midway between pronation and supination.

Question 15

Why is there a valgus angle during extension?

Answer 15

The trochlear is angled obliquely.

Question 16

What is the carrying angle? Is it greater in males or females?

Answer 16

Carrying angle is formed between shaft of the humerus and the ulnar. This angle is greater in females than in males (in females >15 degrees, in males it is between 10 -15 degrees).

Question 17

Is carrying angle greater in adults or children?

Answer 17

adults

Question 18

What is the function of the anconeus?

Answer 18

anconeus pulls skin out of the way during tricep extension

Question 19

What articulates in the proximal and distal radioulnar joints?

Answer 19

Proximal radioulnar joint is between radial notch of the ulna and the radial head.

Distal radioulnar joint is between ulnar notch and the ulnar head.

Question 20

What type of joint is the radioulnar joint?

Answer 20

pivot joint

Question 21

What is the motion that takes place at the radioulnar joints?

Answer 21

pronation and supination

Question 22

How are the fibers of the interosseus membrane arranged?

Answer 22

Interosseus membrane fibers are oriented obliquely and this directs the force obliquely.

Question 23

How much of the force transmitted from ulnar to the radius proximally and distally?

Answer 23

proximally only 20% of force is transmitted to radius.

Distally 80% is transferred to radius,

Question 24

What is a likely consequence of fracture at one end of the radius or the ulna?

Answer 24

Fracture at one end may lead to dislocation at the other end.

Question 25

What is a sacciform recess?

Answer 25

Capsule is lax inferiorly at the neck of the radius which forms the sacciform recess allowing smooth movement of radius against ulna.

Question 26

What ligaments stabilize the proximal radioulnar joint?

Answer 26

The annular ligament The quadrate ligament (goes inferiorly and inserts onto the neck of the radius) Interosseus membrane

Question 27

What is a pivot joint?

Answer 27

Pivot joint is where a joint moves within a ring against another ring.

Question 28

What is the ring in the proximal radioulnar joint?

Answer 28

The annular ligament.

Question 29

What is the main nerve supply of the proximal radioulnar joint?

Answer 29

Median nerve Musculocutaneous nerve Radial nerve

Question 30

What is the blood supply of the proximal radioulnar joint?

Answer 30

Deep radial and radial artery branches.

Question 31

What kind of joint is the distal radioulnar joint?

Answer 31

pivot joint; synovial

Question 32

What ligaments reinforce the distal radioulnar joint?

Answer 32

Anterior and posterior radioulnar ligaments interosseus membrane

Question 33

What is the nerve supply of the distal radioulnar joint?

Answer 33

Median interosseus nerve Radial interosseus nerve

Question 34

What is the blood supply of the distal radiounar joint?

Answer 34

Anterior interosseus artery Posterior interosseus artery.

Question 35

What is the most stable position for the distal radioulnar joint?

Answer 35

Midprone postion

Question 36

How is rotation different at the proximal and distal radioulnar joints?

Answer 36

distally radius moves completely anteriorly to ulnar. Proximally radial rotation is limited by capitulum and the annular ligament.

Question 37

What are the origin and insertion of the pronator teres?

Answer 37

Origin the medial epicondyle Insertion the shaft of the radius.

Question 38

What are the origin and insertion of the pronator quadratus?

Answer 38

from shaft of radius to shaft of ulna.

Question 39

What muscles assist in pronation?

Answer 39

FCR PL Brachioradialis (when forearm is midprone)

Question 40

What muscles assist in supination?

Answer 40

Extensor pollicis longus Extensor carpi radialis longus

Question 41

What is another function of supinator?

Answer 41

supinator also is pierced by the radial nerve

Question 42

What can happen to proximal radioulnar joint when falling on a flexed elbow? What age groups are more likely to get this injury?

Answer 42

dislocation (more common in children due to lax ligament)

Question 43

What happens during a dislocation of the proximal radioulnar joint?

Answer 43

Radial head gets displaced -> muscle pulls radial head superiorly after it leaves the annular ligament.

Question 44

How is a dislocation of the proximal radioulnar joint reduced?

Answer 44

While in flexion: Supinate forearm -> Push proximally

Question 45

What are some things that can go wrong with the H-U and R-U joints?

Answer 45

olecranon bursa can get inflamed. Epicondylitis can occur depending on which is overused. (flexor compartment uses medial epicondyle and extensor compartment uses lateral epicondyle)

Question 46

What structures can be affected by an avulsion fracture in the H-U and R-U joints?

Answer 46

Avulsion fractures can affect: medial epicondyle olecranon process coranoid process styoloid process

Question 47

What is the resultant condition from a supracondylar fracture?

Answer 47

Volkmann's ischaemic contracture (thinning of forearm muscles causing contracture)