Physical therapy, such as pricking and heating the skin or subcutaneous tissue and so on, began in the primitive ages in the East and West, and has a long tradition till today. It had developed and systematized about two thousand years ago in China so that acupuncture and moxibustion were administered on meridians and therapeutic points on body surface. The original textbook is the Nei Ching, or the classic of internal medicine, traditionally ascrived to the legendary Yellow Emperor (Huang Ti).
The system of Oriental medicine is that every syndrome is diagnosed and determined by inspection, question, auscultation and palpation. We detect changes of meridian (Kei-raku in Japanese) and therapeutic points (Kei-ketsu in Japanese) using the above mentioned diagnostic methods. It is most important to palpate meridian and points. Consequently, we try acupuncture and moxibustion on the meridian and points, control the body reactions and treat illness.
There are fourteen meridians on human body surface in which Ki (energy) and Ketsu (humor) flow. The flow of energy and humor are the origin of life phenomenon and illness occurs when energy and humor increase, decrease or decay. Meridians are the line of energy circulation in Oriental medicine which correspond to the circulation of blood or function of nervous system in Western medicine.
Therapeutic points on all the body amount to about 660, distribute on meridians and clinically observed as tenderness, pain by pinching, induration, pulsation, chill or hotness, hyper or hyposensitiveness, and muscle strain or relaxation.
The stimulation on the therapeutic points improves unusual meridian state because the points are diagnostic and simultaneously therapeutic points.
At first, the author carried out a study of pain threshold of the skin to clarify rationality of using excoriation or tenderness to detect therapeutic points. Further, thermography and threshold determination by Hardy's Pain Meter were used. After that the author carried out an experimental investigation with plethysmography on meridian and therapeutic points from the viewpoint of subcutaneous circulation. A working hypothesis was postulated that meridian and points correspond to a reactive system which correlates to nervous and circulatory systems in human body. Accordingly, the author would like to prove the existence of meridian and point objectively. The following is the result of the experiments.
1. The distribution of pain threshold of the skin, meridian and point.
In the first place, the author divided the surface of trunk in five adult males in one centimeter square plots. The number of plot is about 2000 (from 41 to 49 rows, 25 columns) per one person from 7th certical process to the horizontal line of iliac crest (back) and from the horizontal line below clavicle to the horizontal line of iliac spine (front). Secondly, I measured pain threshold on all the plots and observed the dorso-lumbar and thoraco-abdominal distributions. Moreover, I measured it on four usual therapeutic points in daily use and those non-therapeutic points on extremities for control. Thirdly, I checked meridian and points on the distribution table by anatomical sites, for example nabel, mamilla, sternum, scapula, spinal process and etc., Forthly, I determined skin temperature using thermography.
(1) The type of the distribution of pain threshold in thoraco-abdominal and dorso-lumbar regions were the same and symmetrical in both side. The distributions are nearly normal in type and the range of threshold is narrow because of small standard deviation. Characteristic is that thoraco-abdiminal region shows low threshold portions on the sternal part, the place of Rectus Abdominis, and hypocondrium, and dorso-lumbar region shows high threshold on scapular regions, vertebral column between both scapulae, and lumbar vertebral column regions.
(2) On the viewpoint of pain threshold distribution, there are longitudinal patterns

The purpose of this study was to investigate changes in muscle strength of the quadriceps femoris after intraarticular acupuncture treatment of the affected joint in subjects with unilateral osteoarthritic knee. Isometric muscle strength was measured by standard dynamometry at 90 degree knee flexion when the subjects contracted the quadriceps muscle slowly and maximally without any pain.
In the preliminary experiment, the repeated measurement yielded a high reliability coefficient (correlation coefficient r=0.95, there is no significant difference between the two means) in the affected knee as well as the normal side for 19 patients with osteoarthritic knee.
Nine subjects, whose muscle strength of the affected side had fallen by more than 20% compared with the normal side, participated in the study. An acupuncture needle was inserted into the point where the tenderness of the affected meniscus was marked. The results revealed a noticeable increase in muscle strength of the quadriceps femoris in the affected side from 14.3±2.2kg before acupuncture to 22.9±3.0kg after intraarticular acupuncture (p<0.001), with no significant change in the normal side from 26.0±2.4kg to 27.1±2.8kg (p>0.05).
A hypothesis was formulated that the dicreased muscle strength of the quadriceps femoris in the osteoarthritic knee results from reflex inhibition from joint receptors and that intro-articular acupuncture has a disinhibition effect on this inhibition of the extensor muscle activity.

We report the effect of electrical acupuncture therapy (Tsukuba method) on 10 patients with primary osteoarthritis of the knees.
We applied acupuncture to the sites of muscle induration and tenderness determined by physical examination and palpation. Pains during walking and when standing -up were releaved in all patients who received the treatment. Activities in daily life showed various responses to our treatment. No improvement in symptoms was found in three patients when they were going up and down staircases or sitting on tatami with their knees fully flexed. We consider that these differences in response are related to the degree of myatrophy, contracture, and stenosis of the joint space.