"What do chiropractic adjustments do?" Great question! 

Most people associate the Chiropractic Adjustment with improving Back Pain, Neck Pain, Headaches. 

There is more to it. The question is a little broader than most people would realize. I believe this is one of the challenges of explaining why Chiropractors use an adjustment to people.

In a way the question, is a little like asking what's the function of medicine… It depends on the medicine and the person taking it.

This is why we, collectively as Chiropractors, tend to default to a broad conceptual answer as to the purpose of adjustments by saying an adjustment… 

• Restores normal function and communication in the nervous system between the body and the brain. This is a statement looking at how an adjustment can effect the nervous system and generally the brain.
• Other times, a Chiropractor might talk about more local effects of an adjustment by saying that it improves the motion of a joint, reduces muscle spasms, and the associated effects of reducing pain. 

So we tend to talk about either a local effect or a more global effect when discussing an adjustment.

It gets a little more complicated though because we can not separate the local effects from the central effects that has many consequences in the nervous system. 

Speaking more locally and specifically to the spine though, losses of normal motion in a segment will result in several problems including the breakdown of the joint and cartilaginous disc. 

The spinal disc as a slightly moveable cushion between vertebra. 

The disc essentially does not have a blood supply. It relies upon movement to get necessary supplies, fuel, and Oxygen into the disc. 

Losses of movement result in losses of this supply. This is considered to be a primary cause of degeneration ('wear and tear') in the disc and has been reported in the literature going back to the 1970's. Recent research has continued showing similar changes. 

One of the principle benefits of the Chiropractic Adjustment is to improve motion, in this case we're talking about the spine but it can help any joint – whether it's in the spine (neck or back), ribs, extremities (anything from shoulder to wrist and hand; from hips to ankle and foot), and the TMJ (the jaw).

The adjustment also can quickly improve muscle tone. A fast stretch of a tight muscle causes a reflex that resets the small receptors in the muscle that govern length.

The muscle spindle receptors are the only receptor in the body that have the ability to change in this way and one of the secrets to really understanding Chiropractic Adjustments.

Interestingly, a slow stretch has the opposite effect.

You can feel this yourself if you attempt to bend forward at the waist while sitting on the floor. This will cause a slow stretch on several muscles including the hamstrings (the large muscles on the back of your thighs). If you put your hand over the back of your thigh as you stretch, you will feel it contract.

If you have a tight muscle and you stretch it, it will react in the same way… at least initially.

Returning to the neck and back, "Why does an area of the spine lose movement?"