MSK - Elbow Joint and Wrist

Question 1

What are the three major ligaments associated with the elbow joint?

Describe their origins and insertions.

What are their functions?

Answer 1

Radial collateral ligament - fan like, attaches between the lateral epicondyle of the humerus and annular ligament of the radius below. It keeps the head of the radius and capitulum in close association.

Ulnar collateral ligament - triangular, attaches to the medial epicondyle of the humerus and the Coronoid process and olecranon of the ulnar. It consists of three bands, the strong anterior band, fan like weak posterior band and slender oblique band which deepens the socket for the trochlear of the humerus

Annular ligament - surrounds the lower part of the head of the radius and maintains its contact with the radial notch of the ulnar

Question 2

What is the origin and insertion for the radial collateral ligament?

What is its function?

Answer 2

Fan like, attaches between the lateral epicondyle of the humerus and annular ligament of the radius below.

It keeps the head of the radius and capitulum in close association.

Question 3

What is the origin and insertion for the ulnar collateral ligament?

What is its function?

Answer 3

Triangular, attaches to the medial epicondyle of the humerus and the Coronoid process and olecranon of the ulnar.

It consists of three bands, the strong anterior band, fan like weak posterior band and slender oblique band which deepens the socket for the trochlear of the humerus

Question 4

What is the origin and insertion for the annular ligament?

Answer 4

Surrounds the lower part of the head of the radius and maintains its contact with the radial notch of the ulnar

Question 5

What are the main flexors of the elbow?

What muscles produce extension of the elbow?

Answer 5

Brachialis
Biceps brachii
Brachioradialis

Triceps and anconeus

Question 6

Where does supination and pronation occur?

What muscles is supination produced by?

When do these muscles NOT act together?

Answer 6

Proximal radioulnar joint

Supinator and biceps brachii

Always act together except when the elbow joint is fully extended

Question 7

In what joint does pronation occur?

What muscles produce pronation?

Answer 7

Proximal radioulnar joint

Pronator quadrus and pronator teres

Question 8

What are the names of the two important bursae around the elbow joint?

Why can they become inflamed?

When is pain most severe?

Answer 8

Subcutaenous olecranon bursa - lies in the subcutaenous connective tissue overlying the olecranon. Inflammation - Repeated pressure and friction

Subtendious bursa - lies between the triceps tendon and the olecranon. Inflammation due to repeated flexion and extension in the elbow e.g. Assembly line workers.

During flexion of the forearm - pressure exerted on the inflamed subtendinous olecranon bursa by triceps tendon

Question 9

What may become inflamed during repeated pronation/supination movements?

Answer 9

A bursa between the biceps tendon and the radius

Question 10

What may dislocate when attempting to life a child or swing a child by the hands when the arm is fully abducted?

Answer 10

Dislocation of the radial head

Question 11

When can avulsion of the medial epicondyle occur?

How does it occur?

Answer 11

After a fall which causes severe abduction of the fully extended forearm.

Traction on the ulnar collateral ligaments pulls the medial epicondyle medially.

Question 12

What may cause a posterior dislocation?

Answer 12

A fall on the flexed elbow

Question 13

What type of joint is the distal radioulnar joint?

What muscles are involved in moving it?

Answer 13

Pivot joint - in which the distal end of the radius moves around the distal end of the ulnar

Supinator and biceps brachii

Question 14

What does the interosessous membrane do?

Where is it attached?

Answer 14

Form a fibrous joint between the radius and ulnar

From the radius proximally to the ulnar distally

The membrane keeps the bones in close apposition during the movements of supination and pronation and prevents proximal displacement of the radius if a force is applied to the outstretched hand

Question 15

What type of joint is the wrist/radiocarpal joint?

Where is it formed between?

What ligaments stabilise it?

Answer 15

Condyloid type of synovial joint

Between the distal end of the radius and the scaphoid, lunate, triquetrum

Question 16

What are the three articulation of the elbow joint?

Where do they attach?

What type of joints are they? and what are they surrounded by?

Answer 16

Humeroulnar joint - between the trochlea of humerus and the trochlear notch of ulna

Humeroradial joint - between the capitulum of the humerus and the radial head

Proximal radioulnar joint - between the edge of the head of the radius and the radial notch of the ulnar

Synovial joints - surrounded by a capsule that attaches near the margins of the articular surfaces

Question 17

What lines the fibrous capsule and humerus?

Answer 17

Synovial membrane

Question 18

What nerves are at the elbow?

Answer 18

Radial - passes anterior to lateral epicondyle

Ulnar - posterior to medial epicondyle

Question 19

What are the names of the two bursae that give rise to problems?

Answer 19

Subtendinous olecranon bursa

Subcutaneous olecranon bursa

Question 20

What is the neurovascular supply to the elbow?

Answer 20

Arterial anastomoses formed by collateral arteries and recurrent branches of ulnar, radial and interosseus arteries

Question 21

What is the second most common joint in the body to be dislocated?

What tends to be the direction of dislocation?

What are the concerns of this dislocation?

Answer 21

Elbow - very stable joint, requires considerable force to dislocate

90% posterior

Brachial artery
Median and ulnar nerves

Question 22

What type of joint is the proximal radioulnar joint?

What bones does it include and which parts?

Answer 22

Pivot joint

Head of radius
Radial notch of ulnar

Question 23

Where is the annular ligament attached?

What is the name of the collar that surrounds the annular ligament?

Answer 23

Ulna anterior and posterior to its radial notch

Ligamentous collar

Question 24

What happens anatomically to pulled elbow?

Answer 24

Head of radius subluxates from from annular ligament

Question 25

# Define dislocation Define subluxation

Answer 25

Complete loss of contact of the joint surfaces Partial dislocation of a joint, so that the bone ends are misaligned but still in contact

Question 26

What type of joint is the interosessous membrane? What is the importance of the fibres running inferio-medially?

Answer 26

Fibrous Allows distribution of force from radius to ulna - force can be spread between two bones

Question 27

What parts of bone are at the distal radioulnar joint? What structure gives it joint integrity stability? What allows twisting of the capsule?

Answer 27

Rounded head of ulna Ulnar notch on medial border of radius Articular disk - separates cavity of distal radioulnar joint from wrist cavity Sacciform recess superior extension of synovial capsule

Question 28

What muscles are involved in movement of the radioulnar joint?

Answer 28

Supinator Biceps brachii Pronator quadrus and pronator teres

Question 29

What facilitates supination/pronation? Bones? Ligament?

Answer 29

Head of radius and capitulum Annular ligament Sacciform recesses - extensions of synovial membrane on neck of the radius and at distal radius and ulna

Question 30

What is the sacciform recesses? Where are they found?

Answer 30

Extensions of synovial membrane Neck of the radius and at distal radius and ulna (superiorly from Articular disk)

Question 31

What is the anatomical name of the wrist? What bones are involved? What are the ligaments? What are the roles of each ligaments?

Answer 31

Radiocarpal joint Distal radius Carpus - proximal row of carpal bones (other than pisiform) I.e. Scaphoid, lunate and triquetrum Radial collateral and ulna ligament Palmar radiocarpal ligament- ensure hand follows radius during supination Dorsal radiocarpal ligament - ensure hand follows radius during pronation

Question 32

What are the movements at the wrist? What is abduction limited by?

Answer 32

Flexion/extension Abduction(radial deviation)/adduction (ulnar deviation) Radial styloid process

Question 33

How does a colles fracture differ from a smiths fracture? What is the most common?

Answer 33

Both are fractures of distal radius Colles - Posterior displacement of distal fragment of radius. Distal fracture displaced dorsally. Fall on outstretched hand. Smith - anterior displacement of distal fragments. Distal fracture displaced ventrally. Falling on flexed wrist, tends to be direct trauma of forearm Smiths fractures are less common

Question 34

How does fractures of the scaphoid occur? If you suffer a scaphoid fracture what will be tender? What artery is of importance? Why may repair take several months?

Answer 34

Fall on outstretched hand. Tenderness over anatomical snuffbox Radial artery - wraps around scaphoid and goes back in to innervate it - avascular necrosis - possible sequela. Blood supply to proximal part of scaphoid is poor.

Question 35

What ligaments stabilise the radiocarpal/wrist joint?

Answer 35

Collateral Palmar Dorsal ligaments

Question 36

What are the prime flexors of the wrist? What are the prime moves for wrist extension?

Answer 36

Flexor carpi radialis and flexor carpi ulnaris Extensor carpi radialis longus and brevis Extensor carpi ulnaris

Question 37

Why may radial growth be impaired following a fracture of distal radius?

Answer 37

Fracture of distal radius may extend through the distal epiphyseal plate. During healing there may be premature closure of the epiphyseal plate and radial growth may be impaired.