Snap, crackle & pop – Why do your joints crack?

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Joint cracking is kinda like Marmite; you either love it or hate it!

But what’s actually happening when a joint cracks?

There are a couple of different reasons why your joints may crack or make noise. The sound of the noise can give you a clue as to what’s going on.

Is it a snap, crackle or pop?


Think of clicking your fingers, flicking your thumb quickly over a finger and it makes a ‘snapping’ sound. The same can happen inside the body; a tendon flicking over a bone. People often get very small snapping sounds as they rotate a wrist or ankle, the soft tissue repeatedly flicks over one of the bony structures. Tendons should slide & glide soundlessly over these structures, so snapping is a sign of friction – which can lead to inflammation.

One snapping sensation that can be uncomfortable is a snapping hip. Some people find that as they rotate the hip they experience a deep, sometimes uncomfortable, snapping. There’s a few potential causes for this:

1) External Snapping hip – this is where your IT Band (the band of connective tissue that runs down the outside of the leg, over your hip and thigh) is snapping over a bony prominence.

2) Internal Snapping hip – this is where your psoas tendon (a hip flexor) is catching on a bony prominence.

3) Labral tear – this is where there is a loose flap of cartilage catching within your hip joint. You need seek medical attention for this

Sports Massage, stretching, mobility & rehab work can all help address the causes of these issues. In most cases you will be able to completely resolve a snapping hip through conservative treatment alone. A labral tear can be managed through sports massage and rehab but surgery is often the best case when the tears become more severe.


A crackle is called crepitus. Literally meaning creeping in the joint, other sounds that fit with this are:

  • Grinding
  • Creaking
  • Crackling
  • Grating
  • Crunching

There are a whole range of conditions that can cause crepitus in a joint, from gout to osteoarthritis. But for most of us joint crepitus is either an indication of joint instability, muscles incorrectly firing as you move causing the bone surfaces to move unevenly over another, or from inflammation.

For joint instability you can use Sports Massage and rehab exercises to help address the imbalance. Think of a bike chain that isn’t fitted right, every now and then it will jump a link in the chain – that’s how instability works. Massage is like adjusting the chain tension and oiling the chain so everything can run smoothly.

For inflammation the description I use to describe this is thinking of a cut. If you squeeze a clean wound you’ll often get some clear fluid appear, this is the tissue fluid. If the wound is infected this fluid will be white, more viscous, possibly with some particles in it – white blood cells and other debris are a result of the inflammation. The fluid in joint cavities can behave the same way, if it is more viscous, contains any debris etc you may hear a crepitus as the joint moves.


A pop is known as a cavitation. These can occur spontaneously when you turn your neck to look behind you, stretch you back, or even in your ankles & toes as you walk upstairs. A pain free pop is nothing to worry about!

What causes a cavitation?

There are a few theories behind what is causing the popping noise:

  1. Cracking sounds occur when bubbles form in joints as they are pulled apart
  2. Cavitation within the joint—small cavities of partial vacuum form in the synovial fluid and then rapidly collapse, producing a sharp sound.
  3. Rapid stretching of ligaments.
  4. Intra-articular (within-joint) adhesions being broken.

Although all things are probably happening simultaneously when a joint is popped, it seems the evidence is pointing towards (1) and (2) being the most likely culprits. This makes the most sense as well, think about cracking a knuckle. You’re unable to crack it again immediately. If it were (3) or (4) then it would seem you should be able to repeat the procedure with the same popping noise. But this definitely isn’t the case!

This video shows a functional MRI of a finger in traction. You can see very clearly the point at which the joint cavitates and the ligaments change tension. You can also see a flash of white at this point. The researchers have no idea what this is! Although they speculate that there is a rapid influx of fluid into the joint which would explain why joint mobility increases as a result of cavitation.

Is it a problem my joints make noise?

The quick answer is no.

In reality if a noise in a joint is consistent and doesn’t cause you pain, then its unlikely to be any cause for concern. However if a joint is painful and making any noises, new or old, then its worth seeking some medical attention.

The other thing to look for is a change in the pattern or quality of the noise. If you normally click a lot in your back and the frequency drops suddenly then this may indicate that you’ve increased muscle tone dramatically which could be an injury risk. Also if you’re not normally clicky but your shoulder has started to clunk, then perhaps some joint instability is creeping in.

So check whether its painful, whether the noise pattern has changed or if the range of movement has increased or decreased. Any issues just drop us a line and we can give you some advice! Or book an appointment for a Sports Massage.


Follow Vicki:

Sports Massage Therapist

Vicki Marsh MSc BA (hons) studied at Oxford University before training as a Sports Massage Therapist. With over 12 years experience she specialises in chronic pain & complex cases as well as coaching Crossfit & Weightlifters. She runs specialist workshops, creates online courses and has spoken at events such as COPA on how to grow a successful business.

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