Organ-tracing is that branch of palpation which deals with the outlining of the boundaries and surface markings of a tender organ or part.
Palpaters frequently confuse tenderness of one of the parenchymatous viscera for the tenderness of interlaced and branching nerve filaments, especially in the abdominal region. The fact that the tender area takes on the characteristic shape of one of the viscera is conclusive evidence that an organ, and not nerves, have been traced.
What Nerves Traceable
Any spinal nerve may be traceable for at least a part of its course. The cranial nerves are made inaccessible to palpation by their location, except the spinal portion of the spinal accessory and the terminal portions of the nerves to the face. Likewise the sympathetic trunks, except perhaps in the neck, are untraceable.
Nerve-tracing is comparatively easy in the upper and lower extremities, neck and back. The superficial nerves of the scalp are hard to follow on account of the hair. The superficial nerves of thorax, abdomen, and pelvis are accessible under the conditions mentioned below; the deep or visceral branches, never.
Of those nerves mentioned as traceable, only such as are irritated and consequently swollen and tender, can be followed. If a nerve is very heavily impinged, especially if the impingement be chronic, it is partially or wholly paralyzed and not traceable. If the heavy impingement be acute, or if there be a light impingement serving as a mechanical irritant, nerve-tracing is a real aid to diagnosis.
Proportion of Cases with Traceable Nerves
About one-half of all the cases which visit Chiropractors for adjustment are susceptible of nerve-tracing. In the remaining half it is absolutely impossible to acquire any information in this way. Of the half who are at all susceptible, it is possible in perhaps four-fifths of all cases to secure some accurate or reliable information.
The patient in whom all accessible nerves seem tender to light palpation is hyperesthetic and unavailable for tracing.