ADJUSTMENT/MANIPULATION:
The term adjustment is used when a chiropractor uses a specific line of drive to a joint which is subluxated, meaning it is not moving like it should be. Most frequently adjustments are given to vertebral segments along the spine which are in this subluxated or restrictive state. Theses joints become subluxed or restrictive due to factors like, posture, position, trauma, or repetitive stress. The objective to the chiropractic treatment is to reduce the subluxation to reduce nerve irritation and improve the proper function of a joint.
When the adjustment is given sometimes there is a popping or cracking sound which is an audible release of gas or also known as a joint cavitation. This cavitation is a release of gases which can be either comfortable or a minor discomfort that lasts a short amount of time, especially if the surrounding muscles are in spasm or if the patient is tense.
Sometimes this audible click is not heard, but just felt by the doctor because of the muscles being tense and not able to relax. This is why chiropractors will also do therapy such as muscle stimulation and either apply heat or ice to help assist the muscles in relaxing.