Lecture - The Elbow and Radio-Ulnar Joints

Question 1

Which bones articulate at the elbow joint?

Answer 1

Medially, the trochlear notch of the ulna and the trochlea of humerus
Laterally, the head of the radius with the capitulum of the humerus

Question 2

What angle does the elbow extend maximally to?

Answer 2

170*

Question 3

Which muscles perform flexion of the elbow?

Answer 3

Biceps brachii, brachialis an brachioradialis

Question 4

Which muscles perform extension of the elbow?

Answer 4

Triceps brachii and anconeus

Question 5

What strengthens the elbow joint?

What aspects may be weak?

Answer 5

Strong fibrous capsule and collateral ligaments (medial and lateral)
Hence, posterior and anterior weak as no ligaments

Question 6

Which ligament stabilises the lateral aspect of the elbow joint?
Where does it stretch between?

Answer 6

Radial collateral ligament

Originates at the lateral epicondyle and fans outwards to blend with the annular ligament

Question 7

Which aspect of the elbow joint does the ulnar collateral ligament stabilise? What does it stretch between?

Answer 7

Medial

Extends from medial epicondyle in 3 bands, all of which end up at conoid process or olecranon

Question 8

Which 3 bursae are clinically important in the elbow?

Answer 8

Intratendinous
Subtendinous
Subcutaneous

Question 9

Where are the intratendinous, subtendinous and subcutaneous bursae of the elbow located?

Answer 9

Intratendinous = within triceps tendon
Subtendinous = between olecranon and triceps tendon
Subcutaneous = between olecranon and overlying connective tissue

Question 10

Why might subtendinous bursitis occur?

Which movement would be most painful, and why?

Answer 10

Excessive flexion and extension of the elbow

Flexion more painful as puts more pressure on bursa

Question 11

Why might subcutaneous bursitis occur?

Answer 11

Repeated pressure/friction on the subcutaneous bursa, e.g. from leaning on elbow

Question 12

Which bones articulate at the proximal radioulnar joint?

What about at the distal radioulnar joint?

Answer 12

Proximal - radial head with radial notch of ulna

Distal - ulnar head with ulnar notch of radius

Question 13

What ligament holds the radial head at the proximal radioulnar joint?

Answer 13

The annular ligament

Question 14

How is friction reduced between the radius and the annular ligament?

Answer 14

Annular ligament lined with synovial membrane

Question 15

What movement occurs at the proximal radioulnar ligament?

Answer 15

Radial head rotates within annular ligament, allowing pronation and supination

Question 16

Which muscles perform pronation and supination of the forearm?

Answer 16

Pronation = pronator teres and pronator quadratus
Supination = biceps brachii and supinator

Question 17

Do any ligaments strengthen the distal radioulnar joint?

Answer 17

Yes - posterior and anterior ligaments, and articular disc

Question 18

What does the articular disc at the distal radioulnar joint achieve?

Answer 18

Separates joint from wrist

Binds R and U together during movement

Question 19

What movement occurs at the distal radioulnar joint?

Answer 19

Ulnar notch of radius slides anteriorly over ulnar head - allows pronation and supination.

Question 20

What is the interosseous membrane of the forearm and where is it located?

Answer 20

Sheet of connective tissue connecting the radius and ulna

Stretches between medial edge of radius and lateral edge of ulna

Question 21

What are the functions of the interosseous membrane?

Answer 21

• Holds radius and ulna together during pronation
• Acts as an attachment site for some muscles
• Transfers force from radius to ulna

Question 22

What sort of joint is the elbow joint?

What about the radioulnar joints?

Answer 22

Elbow = hinge type synovial joint

Radioulnar joints = pivot type synovial joints