Spinal Manipulation: What's the crack?

Spinal Manipulation

I’m sure many of you have watched videos that circulate social media of people having their backs ‘cracked’. But what makes that satisfying sound and what does it achieve?

Osteopaths often combine various techniques tailored to your needs, one of which may include a spinal manipulation. Also known as an ‘adjustment’, the technique has been practiced for over 2000 years and involves a quick thrust to a joint over a very short amplitude, thus the name high velocity thrust (HVT).  This technique, commonly used by Osteopaths and Chiropractors for neck and back pain, is often associated with an audible ‘crack’ or ‘click’ (which often feels very satisfying) and can be applied to various joints in the body. Contrary to the old wives’ tale, there is no evidence to suggest that this technique can cause arthritis, which I’m sure many parents have told their children, probably to stop them clicking their fingers at the dinner table. In fact, Dr Donald Unger spent 60 years cracking only the knuckles of his left hand. At the end of which, there was no degenerative differences or ailments. He was awarded an Ig Nobel Prize in 2009 for this trivial research.

Another outdated belief is that the click is produced by bone rubbing on bone. Again, this is not correct. The sound is created within the synovial fluid of a joint (a lubricant within the joint capsule which reduces friction), so no, there is no contact between adjacent bones. This click is produced when the joint slightly separates, creating gas filled cavities or air bubbles which then rapidly dissipate.


What can spinal manipulation achieve?

·         Reduce the swelling of a joint capsule.

·         Reduce muscle tension.

·         Release endorphins (modulate inflammatory processes, promoting analgesia).

·         Increase the range of movement.

·         Relieve back pain.


Does this technique realign your bones or put them back in place?

This is the oldest theory of spinal manipulation and not very accurate. Osteopaths use manipulations every day with various patients, the myth that spinal manipulations crack your bones back in place is only a myth. This was believed many years ago before it was certain what caused the sound during the technique. Practitioners did believe they were ‘putting the bone back in place’, which is believable with the relief that often follows. In my clinical experience, patients who think their bones need popping back in are often often suffering from acute back pain with associated muscle spasm or a restricted joint of the spine, of which manual therapy can help. Don’t worry, your bones won’t pop out!