M01.03.033 Elbow Joint

The elbow is a hinge-type synovial joint connecting the upper arm to the forearm. It plays a crucial role in the movement and function of the upper limb. In this article, we will examine the anatomy of the elbow joint, including its articulating surfaces, movements, stability, and clinical relevance.

1. Structures of the Elbow Joint

Articulating Surfaces

The elbow joint consists of two main articulations:

1. Trochlear notch of the ulna and the trochlea of the humerus
2. Head of the radius and the capitulum of the humerus

• Note: The proximal radioulnar joint is found within the same joint capsule as the elbow but is often considered a separate articulation.

Joint Capsule and Bursae

The elbow joint is enclosed by a strong, fibrous capsule that strengthens the joint. The capsule is thickened medially and laterally to form the collateral ligaments, which stabilize the elbow during flexion and extension.

Bursae in the Elbow Joint

• Intratendinous olecranon: Found within the tendon of the triceps brachii.
• Subtendinous olecranon: Between the olecranon and the triceps tendon, reducing friction during arm movement.
• Subcutaneous olecranon bursa: Located between the olecranon and the overlying connective tissue, commonly implicated in olecranon bursitis.

Ligaments of the Elbow Joint

• Radial collateral ligament: Located on the lateral side of the joint, it extends from the lateral epicondyle and blends with the annular ligament of the radius.
• Ulnar collateral ligament: Originates from the medial epicondyle and attaches to the coronoid process and olecranon of the ulna.

Blood Supply

The elbow joint receives its blood supply from branches of the brachial artery, providing rich circulation to the surrounding tissues.

Innervation

• Medial nerve
• Musculocutaneous nerve
• Radial nerve
• Ulnar nerve

2. Movements of the Elbow Joint

The elbow functions as a hinge-type synovial joint, primarily allowing for the following movements:

• Note: Pronation and supination occur at the radioulnar joints, not at the elbow.

3. Clinical Relevance

Injuries to the Elbow Joint

1. Bursitis

• Subcutaneous bursitis: Caused by repeated friction or pressure, leading to inflammation and potential infection. Common in individuals who experience falls on the elbow.
• Subtendinous bursitis: Caused by repetitive flexion and extension, often seen in workers who perform repetitive tasks.

2. Dislocation

• Elbow dislocation commonly occurs when a child falls with the elbow flexed. Most dislocations are posterior, and the ulnar collateral ligament is usually torn. The dislocation may also involve the ulnar nerve.
• Note: Elbow dislocations are named based on the position of the ulna and radius, not the humerus.

3. Epicondylitis (Tennis Elbow and Golfer’s Elbow)

• Tennis elbow (lateral epicondylitis): Pain in the lateral epicondyle due to overuse of the common extensor tendons, often seen in tennis players.
• Golfer’s elbow (medial epicondylitis): Pain in the medial epicondyle due to overuse of the flexor tendons, commonly seen in golfers.
  • Mnemonic: Tennis players aim for the lateral side, while golfers aim for the middle of the fairway.

4. Supracondylar Fracture

• Common in children due to a fall on an outstretched hand. It is typically a transverse fracture and may cause damage to the brachial artery, leading to Volkmann’s ischaemic contracture, resulting in fibrotic and shortened flexor muscles.
• Note: Neurovascular assessment is crucial as the injury may affect the radial, ulnar, or medial nerves.

4. Points to Remember

• The elbow joint allows for flexion and extension, while pronation and supination occur at the radioulnar joints.
• The elbow is stabilized by a combination of ligaments, including the radial and ulnar collateral ligaments.
• Common elbow injuries include bursitis, dislocation, epicondylitis, and supracondylar fractures.
• Early recognition and management of elbow injuries are critical to prevent long-term dysfunction or complications.