Why Do Chiropractors Crack Your Back?

Chiropractors don’t actually crack your bones. The popping sound you hear during an adjustment comes from a rapid pressure change inside the joint, which forms a small gas cavity in the fluid that lubricates it. It’s called cavitation, and it’s a by-product of the adjustment rather than the point of it.

If you’ve had an adjustment before, you’ll know the sound. If you haven’t, it’s often the very thing that puts people off booking. Either way, it’s worth knowing what is actually happening.

What causes the cracking sound?

Your joints are wrapped in a capsule containing synovial fluid, which keeps them moving smoothly. That fluid has gases dissolved in it. When a joint is moved quickly towards the end of its normal range, the pressure inside the capsule drops sharply and a gas cavity forms. The sound is that cavity forming.

Researchers have filmed cavitation happening in real time using MRI, which also corrected a long-held assumption: the sound is the cavity forming, not a bubble bursting. That imaging was done on finger joints, where the movement is easiest to capture, but the same mechanism applies to the joints of the spine.

Nothing is being broken, forced out of place, or put back. No bones are cracking.

So why adjust the joint at all?

An adjustment is a controlled, specific movement applied to a joint that isn’t moving as well as it should. The aim is to improve how that joint and the surrounding muscles are working.

Your chiropractor chooses the technique based on assessment: your history, how you move, what brought you in, and what suits your body. Some techniques produce a sound. Others, such as instrument-assisted adjustments, usually don’t.

So whether you hear a pop tells you very little. What matters is the assessment behind the adjustment, the technique chosen for you, and how your body responds to it.

By Dr Olivia Alysandratos, Chiropractor

Reference: Kawchuk GN, Fryer J, Jaremko JL, Zeng H, Rowe L, Thompson R. Real-Time Visualization of Joint Cavitation. PLOS ONE. 2015;10(4):e0119470. doi:10.1371/journal.pone.0119470

FAQs

Common questions about the cracking sound

Plenty of people worry about this; whether it’s safe, whether it causes arthritis, or whether they should be cracking their own neck at home. The questions below are the ones we’re asked most often.

If yours isn’t here, our chiropractors in North Fitzroy are happy to talk it through – get in touch or book an appointment.

What causes the cracking or popping sound during a chiropractic adjustment?

The cracking or popping sound, often heard during a chiropractic adjustment, is caused by the release of gas bubbles from the joint. This process is called “cavitation.” When a joint is adjusted, the pressure inside the joint changes, allowing gases like oxygen, nitrogen, and carbon dioxide to escape from the synovial fluid, creating the audible sound.

Does the cracking sound mean the adjustment was successful?

Not necessarily. The sound is simply a byproduct of the joint movement and gas release. A successful adjustment is determined by the improvement in joint mobility, alignment, and overall function, not by the presence or absence of a cracking sound.

Is the cracking sound harmful?

No, the cracking sound itself is not harmful. It is a natural phenomenon that occurs during joint adjustments. However, chiropractic adjustments should always be performed by a qualified professional to ensure safety and effectiveness.

Why don’t I always hear a cracking sound during my adjustments?

Not all adjustments produce a cracking sound. Factors such as the type of adjustment, the joint being worked on, and individual anatomy can influence whether or not you hear the sound. The absence of a sound does not mean the adjustment was ineffective.

Does the cracking sound mean my bones are being moved or broken?

No, the sound is not related to bones breaking or being damaged. It is simply the release of gas from the joint. Chiropractors use controlled and precise techniques to adjust joints safely and effectively.

Is it safe to try to make my joints crack on my own?

It is not recommended to attempt self-adjustments or force your joints to crack. Improper techniques can lead to strain, injury, or instability in the joints. Always seek care from a licensed chiropractor for safe and effective adjustments.

Will the cracking sound cause arthritis or joint problems in the future?

There is no evidence to suggest that the cracking sound during chiropractic adjustments causes arthritis or long-term joint problems. In fact, chiropractic care can help improve joint health and mobility when performed by a qualified professional.

Can everyone experience the cracking sound during adjustments?

Not everyone will hear the cracking sound during adjustments, and that’s perfectly normal. The sound depends on factors like joint structure, the presence of gas in the joint, and the type of adjustment being performed.

Should I be concerned if I don’t hear a cracking sound?

No, the absence of a cracking sound does not mean the adjustment was unsuccessful. Chiropractors focus on restoring proper joint function and alignment, which can occur without any audible sound.