Here a short video by Melisa Brown where she demonstrates how to do a certain part of a Thai hand massage – the part that many people are not comfortable with, when the massage therapists “pops” your fingers – it’s when a massage therapists does that pulling movement on your finger that can often create this “cracking” sound.
Some people are worried whether this is healthy or not. It really is just the sound of small air bubbles in the synovial fluid of your finger joints. Synovial fluid is the liquid substance that lubricates your joints. This fluid is filled with gases like oxygen, carbon dioxide and nitrogen. What happens when a massage therapist – or you yourself – pull on your finger or toe joints in that certain way, is that your joint capsule gets stretched, and thus gas is rapidly released, and it thus creates bubbles. That’s what makes the sound.
If you want to crack your joints again, it will take some time until the gases returned to the synovial fluid.
Melisa here demonstrates how the finger joints are rotated and then quickly pulled. You might want to try this out yourself, but many people do not really like the feeling.
How to Give a Thai Hand Massage — powered by eHow.com