Why Do Joints Crack? Causes and Myths Explained

Joints are complex structures at the juncture between two bones. Some joints are mobile and allow a relatively wide range of movements. However, in certain situations, these joints crack and make noises. But what is the reason for this sound, and, above all, does it damage the health of the joints? We are looking into this question…

Differentiating Between Two Types of Cracking Joints

We can group joint cracking into two main categories, namely voluntary cracking and involuntary cracking.

Voluntary Cracking

This refers to the people who crack the joints of their fingers, their toes, or who crack their neck. This phenomenon is relatively easy to explain. Movable joints are covered with a protective capsule called the “synovial membrane“. It is made up of connective tissue, and it contains the synovial fluid. This fluid has a very important role within the joint. Indeed, it allows to nourish, lubricate, and therefore to protect the articular structures and prevents the two bones from rubbing together.

Note that synovial fluid contains different types of gases, including carbon dioxide, oxygen and nitrogen. Thus, when we voluntary crack a joint, we are putting a significant amount of pressure on it. The gas contained in the synovial fluid then forms bubbles, which end up bursting.

Thus, the cracking sound does not come from the joint structures rubbing together or hitting each other, but rather from the sound produced when the bubbles pop.

Involuntary Cracking

As previously mentioned, involuntary cracking can occur in different situations: sudden changes in body position, falls, doing a physical activity, etc. in these situations, the cracking is instead produced in the tendons or ligaments.

Tendons are ends of a muscle, which, like a rope, connect the muscle to the bone within the joint. As for the ligaments, they are bands of connective tissue that connect two bones together in a single joint.

During joint movements, tendons and ligaments stretch and rub against other parts of the joint, such as bone. This is what can cause a cracking noise. If no pain accompanies the cracking sound, you should not be overly concerned.

When Should We Worry About Cracking Joints?

As a general rule, it is involuntary crackling that can pose a risk to the structures of the joint. In the last section, we explain why involuntary cracking, for example, in the joints of the fingers, should not be of concern.

Involuntary cracking from a sudden movement, wrong move or fall should be taken seriously when accompanied by the following signs: sharp pain in the joint, sudden swelling or problems walking (joints in the legs). These symptoms are usually a sign of more serious damage to the tendon or ligament. In this case, it is important to see a doctor for a more accurate diagnosis. A consultation with a physiotherapist may also be relevant to better understand what happened.

Does Cracking Your Knuckles Lead to Osteoarthritis: Myth or Reality?

You have probably been told that cracking your knuckles, for example, will lead to joint point from premature osteoarthritis. However, this has been proven to be a myth.

An allergist named Donald Unger conducted an experiment on himself. He cracked the knuckles of one of his hands for 60 years. His goal: to prove to his mother that her warnings about a premature risk of osteoarthritis were wrong. This is indeed the conclusion at which he arrived. Although Dr. Unger’s study was of little actual scientific value (having a single subject in the study), other experts have done more elaborate studies. In the end, they came to the same conclusions.

In short, cracking joints, when not accompanied by other symptoms, is harmless to joint health. If, however, you sustain an injury to your ankle, knee or other joint in the body, don’t wait for it to pass. Consult a healthcare practitioner to prevent this injury from affecting your long-term mobility.