Particular skin points of the human body are characterized by having a very low impedance. It has been shown that more than 90% of particularly low impedance skin points coincide with traditional Chinese Medicine acupuncture points [1]-[3]. The bioelectric properties of acupuncture points are not clearly understood yet but it is by now generally accepted that both meridians and acupuncture points have lower electrical resistance or impedance than nearby surrounding tissues [4]-[6]. These low impedance points are thought to be the result of sensory and motor nerves emerging from deep tissue to superficial layers of the skin [7] and the change in impedance at acupuncture
points is reported anywhere from between 1/2 to 1/20 of the impedance of the surrounding skin [8]-[9]. Small electrical potentials can be recorded on the skin at the terminal points of acupuncture meridians and the results are replicable under controlled experimental conditions
[10]. As a result of these potentials, the current produced ranges from a few nA to several hundred nA, which can be recorded by an external measuring device. The electromotive force producing these endogenous currents results from electrical potentials at the acupuncture points on the skin and it is a function of the internal resistance of the point. Figure 1 shows the typical behaviour of the electrical resistance on an acupuncture point.

 

 

Figure 1: Electrical resistance of the acupuncture point.

 
The resistance is a function of the cutaneous region, skin humidity and pressure of the measurement electrode. The arrow in the figure highlights the strong decrease of resistance in the acupuncture point. The z coordinate reflects the resistance (Ω) and the x-y coordinates the movement of the electrode on the cutaneous surface (mm). In a previous work [11] a non-invasive probe was described, through which small electric currents can be measured at characteristic points on the skin in a replicable manner. The main purpose of the work presented here is the development of an effective graphical man-machine interface to facilitate the use of the non-invasive probe and to allow the correct evaluation of the measurements.