Crepitus and the Crackling Sounds in Your Joints

Crepitus is the abnormal popping or crackling sound in either a joint or the lungs, which may be faint or loud enough for people to hear. It is often accompanied by a popping or crunching sensation that may sometimes be uncomfortable or painful.

Close up of man cracking his hands
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Crepitus in the joints is typically related to joint damage. Crepitus in the lungs is caused when collapsed or fluid-filled air sacs abruptly open upon inspiration.

Crepitus is not so much a condition but rather a descriptive characteristic that healthcare providers use to pinpoint the source of the problem. The term "crepitus" is derived from the Latin for "rattling" or "creaking."

Crepitus of the Joints

Crepitus may occur in tandem with a joint disorder or entirely on its own. As a symptom, it is not inherently problematic. Cracking your knuckles, for example, is a form of crepitus wherein tiny nitrogen bubbles in a joint suddenly pop with strenuous movement.

It is generally only a problem when the popping is progressive or is accompanied by symptoms of joint damage, injury, or infection.

Joint Damage

Crepitus can occur when the roughened surfaces of two joints rub together, causing the physical grating of cartilage and/or bone.

If the pain is felt, it is typically related to advanced joint damage and/or the compression of nerves between narrowed joint spaces. It is at this stage that the joint may begin show signs of injury, including swelling, redness, reduced range of movement, and malformation.

Osteoarthritis ("wear-and-tear arthritis") is the most common cause of this, although crepitus can occur with other forms of arthritis, including rheumatoid arthritis, psoriatic arthritis, gout, and juvenile idiopathic arthritis. It can affect any joint of the body but is most common in the knees, hands, feet, lower back, hips, and shoulders.

Joint Inflammation or Injury

Crepitus can also occur in special forms of arthritis or when structures around the joint are inflamed or injured. These types of disorders are usually accompanied by pain and the marked restriction of movement.

  • Bursitis: This is inflammation of the fluid-filled sacs near the joint called bursa. It may be caused by an infection, autoimmune disorder, trauma, or a repetitive use injury. Crepitus can occur when the inner surfaces of an inflamed bursa rub against each other.
  • Tenosynovitis: With this, inflammation builds up in the lining of the tendon sheath called the tenoysnovium, which surrounds a joint tendon. Crepitus can occur when a tendon slides through an inflamed sheath.
  • Patellofemoral pain syndrome (PFPS): Also known as runner's knee, this is caused when the cartilage under the kneecap (patella) is damaged. This roughened cartilage can cause crepitus during knee movement.
  • Temporomandibular joint disorders (TMJ), which are characterized by pain and other symptoms related to problems in the TMJ, the articulations between the jaw and the base of the skull. People with TMJ arthritis can sometimes hear crepitus with jaw movement. TMJ disorders can also result in both a clicking sound and popping sensation as you open your mouth.

Almost any injury of the joint cartilage can cause clicking or popping sounds as the uneven surfaces rub together. Rotator cuff tears and triangular fibrocartilage complex (TFCC) of the wrist are two such examples. Even abnormally-shaped cartilage, such as with discoid lateral meniscus (misshapen disc in the knee), can trigger this effect.

A less common cause of crepitus is scleroderma, a rare disorder characterized by the hardening and tightening of the skin and connective tissues. When this happens, it can cause coarse creaking sounds and sensations as the muscles and tendons rub against inflamed or hardened tissues.

Crepitus of the Lungs

While we typically apply the term "crepitus" to the joints, it can also be used to describe audible crackling sounds in the lungs. Also referred to as crackles or rales, the sounds are related to abnormalities in the lungs, typically accumulation of excess fluid or lung scarring.

Among some of the conditions for which rales are common:

Crepitus of the lungs can usually be detected with a stethoscope but may sometimes be loud enough to be heard unassisted.

Diagnosis and Treatment

If crepitus is detected, the diagnostic process can vary depending on the location the sounds are coming from, the severity, and accompanying symptoms.

Joint Disorders

In some cases, the popping of a joint may be more irritating than problematic and, as such, may not warrant investigation or treatment. If there is pain, inflammation, or restriction of motion, your healthcare provider may order tests to pinpoint the cause. These may include:

  • Imaging tests such as ultrasound, X-ray, or computed tomography (CT) to detect bone or joint injury, or magnetic resonance imaging (MRI) to detect soft tissue damage
  • Blood tests to check for infection or inflammation
  • Antibodies tests to confirm autoimmune disorders such as rheumatoid arthritis
  • Arthrocentesis in which fluid is extracted from the joint space with a needle for analysis in the lab

Treatment may involve ice application and non-steroidal anti-inflammatory drugs (NSAIDs) to alleviate mild to moderate inflammation and pain. Severe cases may require splinting or intraarticular steroid injections to help further reduce inflammation.

Infectious causes of joint inflammation are most often bacterial and may require a short course of antibiotics. Immune suppressive drugs are sometimes used to treat inflammatory autoimmune diseases.

Severe injuries (such as torn tendons, ligaments, or cartilage) may require surgery, typically performed arthroscopically with keyhole incisions. If your mobility or quality of life is significantly impaired, joint replacement surgery may be considered, accompanied by extensive rehabilitation and physical therapy.

When you return to routine exercise, modifications such as opting for low-impact activities and using lighter weights can help keep crepitus in check.

Lung Disorders

Crepitus of the lungs is never considered normal. Depending on your medical history and accompanying symptoms, the following tests may be ordered:

The treatment can vary based on whether the condition is acute or chronic.

Healthcare providers will typically treat bacterial pneumonia or bronchitis with antibiotics. Viral infections may be treated with antiviral drugs but are more often allowed to run their course with bed rest and plenty of fluids.

Chronic conditions usually require lifestyle changes, including smoking cessation, exercise, and the avoidance of airborne irritants. Conditions like COPD will generally require oral or inhaled corticosteroids and bronchodilators. Pulmonary rehabilitation and oxygen therapy can help prevent disease progression and maintain a quality of life.

Pulmonary edema may require the aggressive treatment of the underlying heart failure, ranging from chronic medications to bypass surgery. Surgery may be an option for people with advanced lung disease when all other treatments fail. A lung transplant is a last resort for those who lungs are no longer functional.

A Word From Verywell

Crepitus may be a sign of a serious illness or mean nothing at all. If uncertain about whether a clicking or crackling sound is problematic, always err on the side of caution and get checked out. If there is pain, swelling, redness, or you are suddenly less able to move a joint, do not hesitate to schedule an appointment with a healthcare provider or orthopedist.

However, if you ever hear crackling sounds when you breathe, see your healthcare provider as a matter of urgency whether or not there are any other symptoms. The earlier you do so, the more likely you will be to identify and treat the condition before it turns serious.

Frequently Asked Questions

  • Is cracking your knuckles bad for you?

    As long as you don’t feel pain when you crack your knuckles, there shouldn’t be anything wrong with doing it. If you do have pain, talk to a doctor about the possibility of injury or joint damage. In rare instances, cracking knuckles too vigorously could lead to tendon injuries or joint dislocation, so be careful not to put too much pressure on the joint.

  • What is subcutaneous emphysema?

    This is a condition in which air is trapped under the subcutaneous layer of the skin. It can cause swelling and may result in a crackling sound (crepitus) emanating from the spot when you touch it. If the underlying cause is treated, subcutaneous emphysema should resolve without problems. 

  • Is crepitus a sign of bursitis?

    It can be a symptom. The cracking is usually accompanied by pain if it’s caused by bursitis. If you don’t feel pain, crepitus may not be a sign of any serious problem.

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4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Chandran suja V, Barakat AI. A mathematical model for the sounds produced by knuckle cracking. Sci Rep. 2018;8(1):4600. doi:10.1038/s41598-018-22664-4.

  2. Harvard Health. Knuckle cracking: Annoying and harmful, or just annoying? Published October 27, 2020.

  3. Aghajanzadeh M, Dehnadi A, Ebrahimi H, et al. Classification and management of subcutaneous emphysema: A 10-year experienceIndian J Surg. 2015;77(Suppl 2):673–677. doi:10.1007/s12262-013-0975-4

  4. Conduah AH, Baker CL, Baker CL. Clinical management of scapulothoracic bursitis and the snapping scapula. Sports Health. 2010;2(2):147-55. doi:10.1177/1941738109338359

Additional Reading
  • Firestein, G.; Budd, R.; O'Dell, J. et al. (2013) Kelley's Textbook of Rheumatology (9th ed). New York, New York: Elsevier. DOI: 10.1016/C2009-1-62542-9.
  • Zander, D. and Farver, C. (2017) Pulmonary Pathology: A Volume in the Series: Foundations in Diagnostic Pathology(2nd ed). New York, New York: Elsevier. ISBN-13:978-0323393089.