Cracking of your back, or any other joint in your body really, most often occurs due to a phenomenon known as cavitation. Basically what this means is that, when you move a joint rapidly, the suction inside the joint fluid causes small bubbles to form, which then pop - leading to the cracking sound. When you take a deep breath in, you are likely extending some of the joints in your spine, leading to cavitation.
Although this is the most common cause of 'cracking' (and totally benign, of no medical significance), there are other causes of cracking noises as well that would need to be evaluated. For example, if you have any pain or stiffness in your back, or if you ever notice any weakness, numbness
, or tingling in your arms, hands, legs, or feet, these would all be warning signs that perhaps something else, such as severe back arthritis
, is going on.
Assuming you do not have any of these symptoms, you are probably ok, although it is still best to have your primary care doctor
check things out. If you do have symptoms, then you should make an appointment very quickly.