I read the information on your website about knuckle cracking, and I was wondering if it applies to cracking backs and necks. I know that people often have their backs cracked by friends, etc. because it feels good and seems to relieve tension. Also, when my neck feels tight, I often turn it from side to side until it cracks and feels better. I've heard that chiropractors do some version of this, and call it "realignment." Is this safe? Is there a right or a wrong way to crack a back or neck? Is cracking your back/neck actually therapeutic in some way?
It's hard to say from symptoms alone exactly what causes someone to have a tense or aching back and/or neck. For the vast majority, the culprit is likely stress, overuse, or lack of motion. Poor posture, sitting for long periods of time, reading, and doing computer work with the neck bent forward all strain the back and lead to muscle strain, spasm, and neck or back pain. Students, for example, often do all of these things and carry heavy book bags, which strain the back.
There's probably not a neck or back around that hasn't felt this way, nor hasn't been cracked on purpose or inadvertently by their owners without any negative consequences. Gently turning, rotating, or rolling one's head and neck can alleviate some tension and stiffness while stretching, doing flexibility and strengthening exercises, and taking frequent short breaks from studying will also relieve back pain. Hot baths, soft music, massage, and meditation can help as well. On the other hand, having friends, partners, or other acquaintances crack your neck or back for you can cause serious damage to your vertebrae.
In 1994, the U.S. Agency for Health Care Policy and Research concluded that spinal manipulation is a safe and effective treatment for acute, uncomplicated lower back pain (e.g., for people who have strained their backs from lifting heavy objects.) Chiropractors can realign or "adjust" the vertebrae of people's backs and necks, but only with special equipment and after years of training. They manipulate the body by applying pressure on misaligned joints, and then relieving the pressure by putting the joints back into their proper positions. Chiropractors also evaluate a person's posture and movement to look for and correct joints that are misaligned or not moving freely and fully.
Although chiropractic care is highly rated by many patients who receive it, there's little scientific data supporting its use. The National Institutes of Health (NIH) Center for Complimentary and Alternative Medicine is one agency investigating the use, effectiveness, and safety of chiropractic treatment for muscular-skeletal injuries and disorders.