Excitation or Inhibition
A slight impingement serves as a mechanical irritant to increase the action of the nerve and the functions of the attached peripheral organs. Such stimulation beyond the normal is always followed by a reaction, or fall to subnormal action.
Heavy impingement, especially the impingement due to marked occlusion of foramina, partly or wholly paralyzes the affected nerves. Often the impingement produces only a latent weakness in some organ, a weakness which may be brought to light only through the introduction of some secondary cause which takes advantage of the susceptibility of the organ to produce some definite disease. As an instance of this we may mention typhoid fever. No typhoid case is found without subluxation in the region of the second Lumbar; yet the latent weakness produced by that subluxation may not have been observed until the typhoid germ found a fertile feeding and breeding ground in the weakened tissue and proceeded to multiply there and develop its toxins.