There are many professions around the world today that use spinal manipulation in the treatment of patients. But chiropractic is the only profession in which manipulation, known as adjustment to chiropractors, serves as the main focus of care and education.
That said, there is a great deal of controversy among chiropractors today about whether to use the word manipulation or adjustment to describe what is, in essence, spinal or peripheral joint manipulation. Many chiropractors prefer the word adjustment, which has historical, anatomical, scientific and philosophical relevance. They believe that it differentiates chiropractors from other health-care providers utilizing spinal manipulation, whereas manipulation is a term more widely accepted by allopathic medicine.
So what is an adjustment? The chiropractic adjustment involves the utilization of specific, short-lever, high-velocity and controlled forceful thrusts by hand or instrument (such as an activator tool) that are directed at subluxations. The goal of this corrective pressure is to return joints to their proper position, remove subluxations and restore health to the nervous system.
Leach, R. The Chiropractic Theories: A Synopsis of Chiropractic Theories. Philadelphia: Lippincott Williams and Wilkins, 1986. 15.