[Calculation of thermally caused blood flow changes in a finger using thermographic skin temperature measurements (author's transl)].

The skin temperature changes of the third finger were registered with the help of an infrared camera during a cooling process of the hand and forearm of a male, 38-years-old subject. Using the system of formulae, explained in previous publications [4-7], it was possible to describe the blood flow changes in the finger. The results are: 1. A formula for the "pseudo thermal conductivity" (material constant of the thermal conductivity plus the convective contribution), which is similar to the formula used for theat release of the whole body [4], describes well the experimental results. The "pseudo thermal conductivity" is a measure for the specific blood flow and can be converted into it. 2. The "pseudo thermal conductivity" has a local maximum. 3. The position of the maximum is independent of the tissue temperature. The anatomical properties of the finger seem to determine the position of the maximum. 4. The maximum of the "pseudo thermal conductivity"--and therefore the maximal blood flow--increases stronger than linearly with the tissue temperature.