The mosaic electrical characteristics of the skin

Abstract

The goals of this study are: 1) to characterize the structure of the skin by measuring impedance variations with a suction microelectrode; 2) to correlate the observed impedance variations with dc current pathways through the skin; 3) to characterize the breakdown phenomenon. We constructed a suction microelectrode with a 200-microns internal diameter and performed several tests on two male subjects. Skin impedance measured from different locations on the forearm and palm varied considerably. We found that the average skin impedance on the forearm was larger than the average impedance on the palm and that the ratio between the maximal and minimal skin impedance is larger for the forearm than for the palm. For both the forearm and the palm the magnitude and variance of skin impedance decrease with increasing stimulus frequency. The density of low impedance points observed on the forearm and palm are consistent with the density of dc current pathways through the skin as indicated by traces left on 1-cm2 Ag electrodes when we passed dc current through the skin. The ratio between the highest and lowest impedances decreased as temperature decreased--at low temperatures the skin displayed mostly high impedances. We were not able to break down the skin using the suction microelectrode. The tests with dry and wet electrodes suggest that breakdown is of thermal nature, and that the thermal capacitance of the saline in the suction microelectrode prevents the temperature of the underlying skin from increasing very rapidly. In conjunction with the larger impedance values, this would tend to increase the breakdown voltage.

Migration pathways of hypodermically injected technetium-99m in dogs

“…SuceessNe migration patterns found in type-II experiments could also be explained by this hypothesis. After a cutaneous incision that intersected the migration pathway, the proportion of 99~l'c-pertechnetate migrating longitudinally increased as insulation of the subcutaneous environment improved until insulating conditions were sufficiently appropriate to allow restoration of the linear migration pattern, without the necessity of waiting for the healing process to be completed [7,8]. Individual differences in the length of time required for the reestablishment of 99mTc-pertechnetate migration may reflect differences in terms of the speed of attaining insulation according to factors such as spontaneous healing capacity of each animal, amount of bleeding, and correct positioning and cleanness of the suture borders.…”

“…On the other hand, 99mTc-pertechnetate migration only takes place when the radioactive tracer has been injected at points of low electrical resistance [2] and in the presence of electrical insulation of the subcutaneous environment whether by undamaged skin [3,7,8] or by insulating agents appropriately covering a surgical wound. This suggests that movement of the radioactive tracer may be related to the action of some force of electrical type by means of a mechanism that might be similar to that of capillary electrophoresis.…”

Impact of Surgical Intervention and Postoperative Pain on Electrical Skin Resistance at Acupuncture Points: An Exploratory Study

“…ESR changes are not restricted to APs but the whole skin side of the human body can be described as electrically inconsistent, with the pattern of its distribution being mosaic-like. 30 Despite many investigations, the physiological origin and function of electrical resistance of the skin is still unknown. One theory states that ESR represents a residue of an early coordination system during embryogenesis, but there is little scientifi c evidence to support this theory.…”

Design of Measuring System of ASC (Acupuncture Spot Current) for Constitutional Diagnosis

“…Since Hodgkin's study of action potential, studies on bioelectric characteristics of skin [4][5][6][7][8][9], studies on mathematical models of skin and electrodes [10,11], and studies on stimulus parameters [12] etc were carried out. Such bioelectrical characteristics are diversely shown according to physical activities and individuals, and have been the foundation of bioelectrical signal measurement including EEG and ECG measuring for diagnosis in modern medicine.…”