Adjustments and manipulations are techniques used to restore motion to joints that have lost their ability to move normally.  To fully understand, we must first learn about normal joint mechanics.            

            All joints have an active and passive range of motion.  Active range of motion is the movement a joint makes using only your muscles.  Move a finger back and fourth and notice how far it moves.  At the end of the motion you can push on your finger and it will move a little farther.  This extra motion is the passive range of motion.  The joint should give as you push it into the passive range.

            At the end of the passive range of motion is an area called the paraphysiological zone.  The goal of adjustments is to move the joint beyond the passive range of motion and into the paraphysiological zone.

            As the joint is moved into this special zone a popping sound is usually heard.  This requires great speed and skill and should only be done by someone who has had extensive training.  Adjustments may be used on any joint of the body that has lost its normal joint motion. 

What makes the popping sound?

            When a joint is adjusted the two surfaces of the joints separate.  The popping sound is not made from the bones, but is the collapse of a gas bubble formed in the joint fluid as the joint is separated.  It takes approximately 20 minutes for the joint surfaces to return to their previous position and pressure.  This is why may patients feel �gloose�h after an adjustment.  Adjustments allow the joint to have more freedom and a greater passive range of motion.

How do adjustments work?

�œIncreasing joint motion (mechanical) which causes a decrease of pain (reflex).  You have different types of nerves that sense different types of sensations.  The nerves that sense motion, cold, heat, vibration will override the nerves that sense pain. 

�œStimulating a joint with an adjustment (mechanical) causes relaxation of the muscles around the joint (reflex).

�œChronic pain results in decreased joint mobility, shortening of joint tissues, and the formations of adhesions.  Adjustments stretch shortened tissues and break joint adhesions.  This results in increased joint motion causing reflexes noted above.

�œSometimes a tag of joint tissue will become trapped in the neck or back joints.  This may cause irritation in both the affected and neighboring joints, which leads to muscle spasms and a locked neck or back.  Adjustments can release joint tags. (mechanical)

�œSpinal adjustments stimulate the autonomic nervous system (reflex), which regulates the function of organs.  Some of the effects include changes in blood circulation, skin temperature, blood pressure, blood chemistry, and the diameter of the pupils.

�œCorrecting abnormal joint mechanics provides relief of chronic nerve compression and irritation.  Some patients have a combination of stenosis, or narrowing of the canals that the nerves pass through, and decrease joint motion.  Adjustments will increase joint motion and relieve compression of the nerves, resulting in reflex effects that reduce pain and muscle dysfunction.