A lot of research has been undertaken in the osteopathic field. Some relates to the way the musculo-skeletal system influences general body health and function; that is the actual changes that occur—especially in the spinal region—and the consequences of these changes. This area of research has produced great insight into the physiology and pathology of the body, whilst other research has been concerned with attempts to validate osteopathic diagnostic and therapeutic measures. This has helped to establish more clearly what is, and what is not, valid in these fields but, as with so much of research, more questions are raised as others are answered.
A major area of research was identified in the late 1930's by Dr J. Denslow, who began testing spinal dysfunction by means of pressure meters and electro-myographs (recorders of muscular contraction and relaxation). He was able to show that the areas of dysfunction required a smaller stimulus to produce muscular changes than in normal areas of the spine. In this way he demonstrated for the first time the accuracy of what had previously been the osteopath's subjective assessment through palpation that something was wrong in a particular area.
Having established that thresholds were low in areas of dysfunction, further research was needed to work out why this was so and to analyse the implications. Fortunately for osteopathy this task was undertaken by Professor Irvin M. Korr Ph.D., a biochemist and leading researcher into osteopathy, who showed that when a spinal segment was in this state of over-excitability it could be stimulated, or activated, by pressure or irritation from other apparently normal segments, even some distance above or below it. When the area of dysfunction was anaesthetized it could no longer be made to respond by local pressure, but would still respond to normal segments, above or below it, being pressed. At the time such troubled segments were termed 'facilitated segments'.
Professor Korr realized that pressure was, in general terms, an unnatural test of body response, and he therefore introduced other stimuli to the subject being tested, such as sudden loud noise, painful stimuli, or verbal stimuli (embarrassing questions or faked bad news). In all cases the 'facilitated segments' (the areas of lowered threshold) were the first to show a reaction, and the muscular overactivity in such regions was the last to cease when the subject relaxed. This work was reported by Korr and his associates in 1947, and he described the process as being 'like a neurological lens which focused irritation upon the lesioned segment and magnified its responses.’ 
Investigations were then made into what was happening in such segments to the sympathetic nervous system, and the possible ramifications in the body as a whole. This involved mapping the patient's skin surface for variations in electrical resistance and temperature. This produced a visual record of the sympathetic nervous system behaviour, as reflected by sweat gland activity and blood flow, under the skin, of any given area at a particular moment in time.
This system has been superceded by infra-red photography as well as by the use of sophisticated electronic apparatus which simultaneously measures eight different spinal segments. All this has proved that there exists a correlation between the lesioned segment (area of somatic dysfunction) and the abnormal behaviour of motor and sympathetic nerves that are segmentally related to the lesioned area.
Patterns of Dysfunction
Over the years Korr began to establish consistent patterns of sympathetic nerve function disturbances and specific organ diseases, especially where pain was a major factor, such as pancreatitis, peptic ulcer, gall bladder disease, menstrual pain, colic, kidney stones etc. Often students who had volunteered for assessment were noted as having patterns of dysfunction which later would show up as a specific disease pattern.