Arm, Elbow and Radioulnar joints

Question 1

What type of joint is the elbow?

Answer 1

The elbow is a hinge joint.

Question 2

What bones form the elbow joint?

Answer 2

The humerus (in the arm) joins with the radius and ulna (in the forearm).

Question 3

Answer 3

Question 4

Answer 4

Question 5

What are the primary movements of the elbow joint?

Answer 5

Flexion and extension.

Question 6

What 3 muscles are responsible for elbow flexion?

Answer 6

Brachialis
Biceps brachii
Brachioradialis (secondary flexor)

Question 7

What muscles are responsible for elbow extension?

Answer 7

Triceps brachii
Anconeus

Question 8

Answer 8

Question 9

What is the alignment of the epicondyles and olecranon during elbow extension?

Answer 9

In extension, the medial and lateral epicondyles align with the olecranon in a straight line.

Question 10

What is the alignment of the epicondyles and olecranon during elbow flexion?

Answer 10

In flexion, the epicondyles and olecranon form a triangle and align vertically.

Question 11

Besides flexion and extension, what additional movements does the elbow joint allow?

Answer 11

Rotation of the forearm and wrist, specifically supination and pronation.

Question 12

What happens to the radius during supination?

Answer 12

The radius rotates laterally around its longitudinal axis, so the palm faces anteriorly (superiorly in anatomical position).

Question 13

What happens to the radius during pronation?

Answer 13

The radius crosses over the ulna, turning the palm posteriorly (inferiorly in anatomical position).

Question 14

Answer 14

Question 15

What is the axis of rotation for supination and pronation?

Answer 15

The proximal radio-ulnar joint.

Question 16

What ligament creates a socket for the head of the radius to rotate in?

Answer 16

The anular ligament of the radius.

Question 17

What muscles primarily perform pronation?

Answer 17

Pronator quadratus
Pronator teres
🔹 Additional contribution from flexor carpi radialis (FCR), palmaris longus (PL), and brachioradialis in mid-pronation.

Question 18

What muscles perform supination?

Answer 18

Supinator

Biceps brachii (when power is required, e.g., using a screwdriver)

Question 19

What structure connects the radius and ulna?

Answer 19

The interosseous membrane.

Question 20

What is the function of the interosseous membrane

Answer 20

It transfers forces from the radius to the ulna.

Question 21

How do the fibres of the interosseous membrane change during forearm movement?

Answer 21

Pronation → Supination: Fibres change from a relaxed to a tense state in neutral position, then relax again in supination.

Question 22

What arteries run through the interosseous membrane?

Answer 22

Interosseous arteries.

Question 23

What is the main flexor of the forearm?

Answer 23

The brachialis muscle.

Question 24

Why is the brachialis important in elbow flexion?

Answer 24

It flexes the forearm in all positions and is not affected by pronation or supination.

Question 25

Where does the brachialis attach?

Answer 25

To the coronoid process of the ulna.

Question 26

What are the 3 functions of the biceps brachii?

Answer 26

Supinates the forearm. Flexes the forearm when the hand is supine. Acts as a supinator when the forearm is pronated (screwdriver action).

Question 27

Where does the biceps brachii attach?

Answer 27

To the radial tuberosity.

Question 28

What is the main extensor of the forearm?

Answer 28

The triceps brachii.

Question 29

What joint movement does the triceps brachii perform?

Answer 29

Extension of the forearm at the elbow joint.

Question 31

What is the insertion point of the triceps brachii?

Answer 31

The olecranon process of the ulna.

Question 32

Is the triceps brachii affected by pronation or supination?

Answer 32

No, it is not affected by pronation or supination.

Question 33

What is the role of the anconeus muscle?

Answer 33

It assists the triceps in forearm extension.

Question 34

Answer 34

Question 35

Answer 35

Question 36

Answer 36

Question 37

What type of joint is the elbow?

Answer 37

The elbow is a synovial joint with three articulating surfaces, making it a compound joint.

Question 38

What are the three articulating surfaces of the elbow?

Answer 38

Humeroradial joint - between capitulum of the humerus and concave fovea of the radius. Humeroulnar joint - between trochlea of the humerus and trochlear notch of the ulna. Proximal radio-ulnar joint - between articular head of the radius and radial notch of the ulna.

Question 39

Answer 39

Question 40

Answer 40

Question 41

What is the relationship between mobility and stability in joints?

Answer 41

the greater the mobility, the greater the potential instability and chance of dislocation.

Question 42

What ligaments ensure the stability of the elbow joint?

Answer 42

Radial and ulnar collaterals, annular ligaments.

Question 43

What is the function of the radial and ulnar collaterals and annular ligaments?

Answer 43

These ligaments hold and encapsulate elements of the elbow joint and deepen sockets.

Question 44

Describe the radial collateral ligament

Answer 44

It is fan-like, extends from the lateral epicondyle, and blends with the radial annular ligament.

Question 45

What is the function of the radial annular ligament?

Answer 45

It holds the radial head in the radial notch, supporting pronation and supination.

Question 46

Describe the ulnar collateral ligament.

Answer 46

The anterior band extends between the medial epicondyle and coronoid; the oblique band deepens the trochlea socket.

Question 47

Answer 47

Question 48

What type of joint is the elbow?

Answer 48

The elbow is a hinge joint that joins the distal end of the humerus in the arm with the proximal end of the radius and ulna in the forearm.

Question 49

What is the function of the elbow joint?

Answer 49

The elbow joint is designed to provide freedom of movement of the arm, but this produces mechanical and physical challenges.

Question 50

What structures pass through the elbow joint?

Answer 50

Muscles, tendons, and neurovascular structures need to pass through safely with minimal impact on the function of the joint.

Question 51

Answer 51

Question 52

What are the contents of the cubital fossa?

Answer 52

Median nerve, brachial artery and vein, and biceps tendon.

Question 53

What are the 3 clinical significances of the cubital fossa?

Answer 53

Intravenous (IV) injections use the superficial veins. Catheters can be inserted in the brachial artery. Surgical access to the distal humerus and elbow joint.

Question 54

Answer 54

Question 55

What is the "Funny Bone"?

Answer 55

The ulnar nerve, which is vulnerable due to its position on the medial aspect of the elbow.

Question 56

Where is the ulnar nerve located at the elbow?

Answer 56

On the medial aspect of the elbow, near the medial epicondyle of the humerus and the olecranon.

Question 57

Answer 57

Question 58

Why are olecranon fractures common?

Answer 58

The olecranon is a narrow, exposed bone protrusion, making it vulnerable to fractures.

Question 59

What is the usual characteristic of olecranon fractures?

Answer 59

They are usually displaced and require surgical intervention.

Question 60

How are olecranon fractures treated?

Answer 60

Bone fragments are re-aligned and fixed using pins and wires or plates and screws.

Question 61

Who is most at risk for distal humerus fractures/supracondylar fractures?

Answer 61

These fractures commonly occur in children and the elderly

Question 62

What important structures can be injured with supracondylar fractures?

Answer 62

The radial nerve and/or arteries, requiring careful evaluation.

Question 63

How are supracondylar fractures usually treated?

Answer 63

They usually require surgical repair with plates and/or screws, unless they are stable.

Question 64

What is "Tennis Elbow" (Lateral Epicondylitis)?

Answer 64

A repetitive strain injury causing inflammation of tendons around the lateral epicondyle, most commonly affecting the Extensor Carpi Radialis Brevis (ECRB).

Question 65

What is a common consequence of elbow dislocation?

Answer 65

The ulnar collateral ligament is often torn and may be associated with fractures.

Question 66

Which 3 fractures are commonly associated with elbow dislocation?

Answer 66

Radial head, coronoid process, or olecranon fractures.

Question 67

What additional injury can occur alongside elbow dislocation?

Answer 67

Fracture of the olecranon.

Question 68

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