A measurement system for examining a section of tissue on a patient in which electric current and/or voltages are applied to a patient in at least one location and are measured on the section of tissue to be examined by at least one electrode of a contact surface of the measurement system. As a result, conclusions can be drawn about the interior of the section of tissue to be examined. The electrode is at least partially surrounded by a conductor element for contacting with a potential which deviates from that of the conductor element.