I have a noticeable left sternoclavicular joint that makes a crunchy sound (crepitus) when palpated, without pain, swelling, redness, fever, or limited shoulder motion; what is the likely cause and how should I manage it?

Asymptomatic Sternoclavicular Joint Crepitus

Your painless left sternoclavicular joint prominence with crepitus is most likely benign degenerative change (osteoarthritis), which is the most common cause of sternocostoclavicular joint abnormalities, and requires only reassurance and observation in the absence of pain, swelling, or functional limitation. 1, 2

Clinical Context and Differential Diagnosis

Your presentation—isolated prominence with crepitus but no pain, swelling, erythema, fever, or limited shoulder motion—strongly suggests a benign process. The key differential diagnoses to consider include:

• Osteoarthritis (most common): Degenerative changes are the most frequent cause of sternocostoclavicular joint swelling and can present with crepitus on palpation 3, 2
• Subluxation/instability: Anterior sternoclavicular joint instability can cause prominence and clicking sensations, though typically associated with some discomfort or history of trauma 4, 5
• Inflammatory arthropathies: Conditions like spondyloarthropathies or SAPHO syndrome can affect the sternoclavicular joint, but these typically present with pain and are often bilateral 6, 1

When to Pursue Further Evaluation

You do NOT need imaging or further workup at this time given your completely asymptomatic presentation. However, you should seek medical evaluation if any of the following develop:

• Pain at the joint (especially if progressive or interfering with activities) 1, 2
• Visible swelling, warmth, or erythema (suggests infection or acute inflammation) 3, 2
• Fever or systemic symptoms (raises concern for septic arthritis, which is a medical emergency) 2, 7
• Limited shoulder range of motion (suggests more significant joint pathology) 4
• History of trauma (even minor, as this could indicate instability) 4, 5

Diagnostic Approach If Symptoms Develop

Should you develop concerning symptoms, the evaluation pathway would be:

• Initial imaging: Chest radiography to exclude fracture, infection, or neoplasm, though plain films often miss costochondral and sternoclavicular abnormalities 1
• Advanced imaging: CT with thin slices is the best modality for evaluating the sternocostoclavicular joint and can differentiate osteoarthritis from other pathologies 7
• Bone scintigraphy: 100% sensitive for detecting sternoclavicular joint inflammation in patients with anterior chest wall pain, particularly useful for early detection of spondyloarthritis 6
• Laboratory studies: If infection is suspected, obtain CBC with differential, ESR, CRP, and consider joint aspiration 3

Critical Pitfalls to Avoid

• Do not dismiss new pain or swelling: While osteoarthritis is most common, serious conditions like septic arthritis or neoplasia can present similarly and require thorough evaluation 3
• Posterior displacement requires urgent evaluation: If you ever experience the joint feeling like it's displaced backward (toward your chest), seek immediate medical attention as this can compromise mediastinal structures 4, 5
• Bilateral involvement suggests systemic disease: If both sternoclavicular joints become symptomatic, consider inflammatory arthropathies and seek rheumatologic evaluation 1, 7

Management Recommendation

For your current asymptomatic presentation, no treatment is necessary—simply monitor for any changes. 2 The crepitus you're experiencing represents normal joint sounds in the setting of mild degenerative changes and does not require intervention unless symptoms develop.