The Elbow- Palastanga

Question 1

Classification of the elbow joint

Answer 1

Synovial hinge

Question 2

What is significant about the joint capsule of the elbow

Answer 2

It is shared with the proximal radioulnar joint

Question 3

What features facilitate and promote large range of flexion at the elbow

Answer 3

Anterior and inferior projection of the distal humerus so that the trochlea lies anterior to the shaft
Reciprocated by anterior and superior projection of the trochlear notch of the ulna

Delays contact between the humerus and ulna

Question 4

What is the carrying angle

Answer 4

The lateral deviation of the ulnar axis from the axis of the humerus when viewed from the front

10-15d for men and 20-25d for women

Question 5

Articular surfaces of the elbow

Answer 5

Humerus - grooved trochlea and hemispherical capitulum

Radius- Cupped head
Ulna- trochlear notch with reciprocating curved longitudinal ridge

Question 6

Where is the coronoid fossa and what does it do

Answer 6

Lies immediately above the trochlea of the humerus and receives the coronoid process of the ulna during flexion

Question 7

Where is the olecranon fossa and what does it do

Answer 7

On the posterior surface of the ulna, behind the coronoid fossa, with which it may communicate if intervening bone is particularly thin
Receives the olecranon process of the ulna during extension

Question 8

Describe the joint capsule

Answer 8

Completely surround the elbow and superior radioulnar joints, with no openings in it
Blends with and is strengthened by the collateral ligaments at the sides but is relatively weak ant and post

Question 9

Describe the ulnar collateral ligament

Answer 9

Fans out from the medial epicondyle and has thick and and post bands united by a thinner intermediate band

Question 10

What about the location of the collateral ligaments is significant

Answer 10

Their positioning allows them to lie across the axis of movement in all positions and so they are relatively tense in all positions of flexion and extension.

Impose v strict limitations on ab/ adduction and axial rotation

Question 11

Describe the radial collateral ligament

Answer 11

Strong triangular band attaching above the lateral epicondyle and blending inferiorly with the annular ligament of the radius. Is less distinct than the ulnar collateral

Question 12

How stable is the elbow joint

Answer 12

Bony congruency quite good but still relies on strong collateral ligaments and muscle cuff of triceps, biceps, brachialis and brachioradialis as well as common tendons of extensor and flexor forearm muscles

Question 13

When is the elbow joint most stable

Answer 13

With the elbow flexed to 90d and forearm in mid pronation-supination

Question 14

How do the majority of elbow dislocations occur

Answer 14

Most occur posteriorly through the weak posterior capsule, often associated with fracture of the coronoid process e.g. through fall onto outstretched hand

In children head of radius commonly dislocated as is small and vulnerable to traction forces

Question 15

Describe flexion/ extension of the elbow

Answer 15

Take place about a transverse axis through the humeral epicondyles which bisects the carrying angle and is not at right angles to axis of humerus or forearm

Question 16

ROM and limitations to flexion at the elbow

Answer 16

Active ROM = 145d
Passive ROM = 160d

Limited by contact between arm and forearm

Question 17

ROM and limitations to extension

Answer 17

Strictly speaking ROM is zero as is only relative extension after joint has been flexed

Limited by tension in ant capsule and collateral ligaments

Question 18

Muscles flexing the elbow

Answer 18

Brachialis, biceps brachii and brachioradialis

Primarily brachialis is slow gently movements

Question 19

Muscles extending the elbow

Answer 19

Active by triceps and anconeus

Passive (against gravity) by eccentric contraction of elbow flexors

Question 20

Is abduction/ adduction possible at the elbow

Answer 20

Yes

Small degrees of movement occur during pronation/ supination of the forearm

Question 21

Does bony contact of joint surfaces limit movement of the elbow

Answer 21

Surprisingly no!

Or at least only very rarely in some individuals

Question 22

Which group of muscles is more powerful and what does this mean

Answer 22

Flexors are more powerful so at rest elbow hangs slightly flexed

Question 23

How does joint contact of the elbow change through changing ROM

Answer 23

Generally humeroulnar contact increases from extension to flexion and head of radius establishes more and more contact with capitulum

In extension is no contact between head of radius and capitulum

Question 24

Increasing joint contact are during flexion means what

Answer 24

Joint is more stable during flexion

Question 25

When do the flexor muscles work best

Answer 25

When the elbow is flexed to 90d

here at optimal lengths etc