Shoulder clicking is a common phenomenon experienced by many individuals during arm movement.

This distinctive sound or sensation can vary from harmless joint noises to signals of underlying musculoskeletal issues.

The Anatomy Behind Shoulder Movement

The shoulder is a complex ball-and-socket joint composed of the humeral head fitting into the shallow glenoid cavity of the scapula. This joint is stabilized and guided by muscles, tendons, ligaments, cartilage (the labrum), and fluid-filled bursae. Movement and stability rely heavily on the rotator cuff muscles and the integrity of associated soft tissues.

Common Causes of Shoulder Clicking

1. Gas Bubble Formation (Joint Cavitation)

One benign cause of shoulder clicking is joint cavitation, where small gas bubbles form and then rapidly collapse within the synovial fluid of the joint. This causes the characteristic popping or cracking sound during rapid or specific movements. This phenomenon is similar to knuckle cracking and is generally harmless if not accompanied by pain or dysfunction.

2. Tendon and Ligament Movement Over Bony Structures

As tendons and ligaments glide over the contours during arm movements, they may momentarily snap or slip, producing an audible click. This snapping is often related to the biceps tendon, which can sublux (partially dislocate) from its groove on the humerus.

Dr. Reuben Gobezie, a recognized orthopedic shoulder specialist, notes, "The most common reason for painful clicking and popping in the shoulder is related to biceps tendon instability, which is frequently misunderstood by patients and sometimes by clinicians." This tendon instability can cause not only noise but also pain and weakness.

3. Labral Tears

The labrum, a cartilage rim surrounding the shoulder socket, stabilizes the joint by deepening the socket and securing the ball of the humerus. Tears to the labrum—whether due to trauma, repetitive overuse, or degeneration can lead to a sensation of catching or clicking. Such injuries often produce shoulder instability and pain, especially during overhead or rotational activities.

4. Rotator Cuff Pathologies

The rotator cuff group, responsible for stabilizing and moving the shoulder, can be a source of clicking when inflamed (tendinitis), torn, or irritated by surrounding structures. These conditions can cause tendons to rub abnormally against bones or other tissues, producing a snapping or popping noise often accompanied by discomfort.

5. Bursitis and Inflammation

Bursae are fluid-filled sacs that cushion tendons and bones. Inflammation of these sacs (bursitis) can alter joint mechanics during movement, occasionally leading to clicking or snapping sounds.

When Does Shoulder Clicking Indicate a Problem?

Occasional shoulder clicking without pain or mobility issues is often benign and not indicative of pathology. However, persistent clicking accompanied by pain, weakness, decreased range of motion, or instability should prompt a clinical evaluation. Imaging modalities like MRI, ultrasound, or X-rays may be necessary to diagnose structural damage or inflammation.

Dr. Stephen S. Tower, a renowned orthopedic surgeon, underscores the importance of professional assessment, "While mild shoulder noises are common, the presence of consistent pain and clicking that alters function warrants thorough clinical and imaging investigation to prevent long-term damage."

Shoulder clicking is a multi-factorial symptom resulting from both normal bio-mechanical processes and pathologic conditions. Understanding its various underlying causes from harmless joint cavitation and tendon movements to serious injuries like labral tears and arthritis—allows for appropriate clinical decision-making. When painless and isolated, shoulder clicks are usually benign.

However, persistent clicks with associated pain or dysfunction merit professional evaluation to prevent long-term joint damage.