chiropractic instruments, namely, adjusting tools that can apply, via an instrument tip and in response to a pressure being applied to the instrument tip in a first direction, a straight axial force in a second direction that is substantially opposite to the first direction, wherein the magnitude of the straight axial force is adjustable, and wherein the straight axial force can be simultaneously accompanied by a rotational force selectitvely chosen from three options including no rotational force, a right rotational force, and a left rotational force