Chiropractic is the second largest primary health care profession in the United States today. The following is the American Chiropractic Association's official definition of chiropractic:

"Chiropractic is based on the premise the relationship between structure and function in the human body is a significant health factor and that such relationship between the spinal column and nervous system is the most significant, since the normal transmission and the expression of nerve energy are essential to the restoration and maintenance of good health.

"Chiropractic is a branch of the healing arts which is concerned with human health and disease processes. Doctors of Chiropractic who consider man as an integrated being and give special attention to the physiological and biochemical aspects including structural, spinal, musculoskeletal, neurological, vascular, nutritional, emotional and environmental relationships.

The practice and procedures which may be employed by Doctors of Chiropractic are based on the academic and clinical training received in and through accredited chiropractic colleges and include, but are not limited to, the use of current diagnostic and therapeutic procedures. Such procedures specifically include the adjustment and manipulation of the articulations and adjacent tissues of the human body, particularly of the spinal column. Included is the treatment of intersegmental aberrations for alleviation of related functional disorders.

Chiropractic is a drug-free, non-surgical science and, as such, does not include pharmaceuticals or incisive surgery. Due regard shall be given to the fact that state laws, as well as the nation's antitrust laws, may allow Doctors of Chiropractic to utilize ancillary health care procedures commonly referred to as being in the common domain."

Chiropractic is one of the three major schools of health, the other two being allopathy (traditional medicine) and osteopathy. Chiropractic is based on the understanding that good health depends, in part, on a normally functioning nervous system. Body structures such as cells and organs function by the impulses carried through nerves. When these nerve impulses travel uninterrupted, the organs and cells are able to function normally. When there is interference, the tissues and organs cannot function properly and a state of malfunction may begin, predisposing the body to a disease state and less than optimum health.