Electrical excitability of skeletal muscle postmortem in casework

Abstract

The paper gives a review of the development of methods of postmortem electrical excitability of skeletal muscle for determining the time since death. For practical application in casework, the following method can be proposed: position of electrodes in the orbicularis oculi muscle, stimulation by rectangular impulses of 10 ms duration, 30 mA in a repetition rate of 50/s. The muscular reaction on excitation is graded in 6 degrees according to the spread of movement and the intensity of contraction. To each degree a time information is corresponding (95%-limits of confidence). These 95%-limits of confidence were proved to be valid for cases of sudden natural or traumatic deaths. Exclusions: deaths after chronic lingering diseases (shorter times), fatal hypothermia, haematomas, emphysemas of the eyelid (longer times). The practical application in casework together with the temperature method (Henssge 1988, 1) is described. Applying both methods the death time estimation in the early postmortem interval may be much more precise and accurate than using one method alone.