This technique was developed in Davenport, Iowa by the founder of chiropractic, Dr. Daniel David Palmer. This is the most common and recognized of all the techniques. Every chiropractor is taught the basics of this method in school and it has become the foundation of the profession. Through either static or motion palpation, the doctor can evaluate the positioning and motion between two joints, spinal or otherwise. After determining which joints are dysfunctional, a manual manipulation is performed which consists of a high velocity, low amplitude thrust. This movement can produce what is called a cavitation - a release of nitrogen gas within the disc space. This is the popping noise that most people associate with chiropractic. Despite the flare of Hollywood, the sounds occurring from a chiropractic adjustment are completely safe and effective when the correct precautions are taken.