Differential rigor development in red and white muscle revealed by simultaneous measurement of tension and stiffness

Based on the molecular mechanism of rigor mortis, we have proposed that stiffness (elastic modulus evaluated with tension response against minute length perturbations) can be a suitable index of post-mortem rigidity in skeletal muscle. To trace the developmental process of rigor mortis, we measured stiffness and tension in both red and white rat skeletal muscle kept in liquid paraffin at 37 and 25 degrees C. White muscle (in which type IIB fibres predominate) developed stiffness and tension significantly more slowly than red muscle, except for soleus red muscle at 25 degrees C, which showed disproportionately slow rigor development. In each of the examined muscles, stiffness and tension developed more slowly at 25 degrees C than at 37 degrees C. In each specimen, tension always reached its maximum level earlier than stiffness, and then decreased more rapidly and markedly than stiffness. These phenomena may account for the sequential progress of rigor mortis in human cadavers.     

On the estimation of lay-time by measurements of rigor mortis

Measurements of the torgue to overcome rigor mortis on the legs of 101 male human cadavers at 5 degrees C are reported. There seems to exist an upper limit, which is dependent on the lay-time, above which no value occurs, but below which every value may be found. By calculating the 90% tolerance limits for lay-times grouped at 12-hourly intervals, this upper limit was found to decrease exponentially with lay-time. This may be used for the estimation of maximum lay-times from rigor mortis measurements.     

Factors and circumstances influencing the development of hemorrhages in livor mortis

Petechial hemorrhages or ecchymoses in the skin of the face and/or in eyelids and/or conjunctivae are one important feature in postmortem diagnosis of lethal strangulation. On the other hand, petechial bleedings can occur in various causes of death, especially in cases of neck or thoracic compression, they can occur in acute cardiac failure, as a result of blood or skin diseases or as a postmortem phenomenon. The focus of this investigation (retrospective study of 279 corpses, found initially in a prone position or some other face down position) was to analyse the frequency of postmortem (hypostatic) hemorrhages and factors which may influence their development. Petechial hemorrhages in livor mortis in the skin of the trunk and extremities were found in 110 cases (39%). The frequency ranged from 41% in the side position and 44% in the kneeling position to 50% in the prone position. Increasing intensity of livor mortis resulted in an increasing frequency of hemorrhages, up to 59%. In cases with a body-mass-index (BMI) of more than 26 the frequency of hemorrhages increased up to 64%. In cases without livor mortis when the corpses were found as well as in cases with complete movement of livor mortis after turning the corpses, no hemorrhages were found. If hypostasis was partly or completely fixed, the rate of hemorrhages increased up to 50%, without additional increase in longer postmortem intervals. Obviously postmortem petechiae develop neither very soon nor days after death, but within a period of several hours after death.     

尸僵再形成的实验性研究

目的观察尸僵再形成中肌节长度的变化。方法应用扫描电镜测定不同条件下取材的40只大鼠股四头肌肌节长度,判断再僵直的强度。结果死后未破坏的尸僵肌节的长度明显小于尸僵再形成时的长度。结论肌节长度与尸僵强度呈负相关,说明肌节长度可确定尸僵强度,从而为推断死亡时间提供依据。     

Development of rigor mortis is not affected by muscle volume

There is a hypothesis suggesting that rigor mortis progresses more rapidly in small muscles than in large muscles. We measured rigor mortis as tension determined isometrically in rat musculus erector spinae that had been cut into muscle bundles of various volumes. The muscle volume did not influence either the progress or the resolution of rigor mortis, which contradicts the hypothesis. Differences in pre-rigor load on the muscles influenced the onset and resolution of rigor mortis in a few pairs of samples, but did not influence the time taken for rigor mortis to reach its full extent after death. Moreover, the progress of rigor mortis in this muscle was biphasic; this may reflect the early rigor of red muscle fibres and the late rigor of white muscle fibres.     

Experimental evaluation of rigor mortis. VII. Effect of ante- and post-mortem electrocution on the evolution of rigor mortis

The influence of electrocution on the evolution of rigor mortis was studied on rats. Our experiments showed that: (1) Electrocution hastens the onset of rigor mortis. After an electrocution of 90 s, a complete rigor develops already 1 h post-mortem (p.m.) compared to 5 h p.m. for the controls. (2) Electrocution hastens the passing of rigor mortis. After an electrocution of 90 s, the first significant decrease occurs at 3 h p.m. (8 h p.m. in the controls). (3) These modifications in rigor mortis evolution are less pronounced in the limbs not directly touched by the electric current. (4) In case of post-mortem electrocution, the changes are slightly less pronounced, the resistance is higher and the absorbed energy is lower as compared with the ante-mortem electrocution cases. The results are completed by two practical observations on human electrocution cases.     

Deaths among narcotic addicts in Denmark in 1978 and 1979

Objective measurements were carried out to study the evolution of rigor mortis on rats at various temperatures.Our experiments showed that:(1) at 6 °C rigor mortis reaches full development between 48 and 60 hours post mortem, and is resolved at 168 hours post mortem; (2) at 24 °C rigor mortis reaches full development at 5 hours post mortem, and is resolved at 16 hours post mortem; (3) at 37 °C rigor mortis reaches full development at 3 hours post mortem, and is resolved at 6 hours post mortem; (4) the intensity of rigor mortis grows with increase in temperature (difference between values obtained at 24 °C and 37 °C); and (5) at 6 °C a “cold rigidity” was found, in addition to and independent of rigor mortis.     

Grading rigor mortis with myotonometry--a new possibility to estimate time of death.

Myotonometry has been applied to grade rigor mortis. The myotonometer is a hand-held instrument which gives a mechanical impact against the muscle. The muscle responds with a damped vibration which is registered and treated mathematically. The period and the logarithmic decrement of decay of the vibrations were found to change with the development of rigor mortis. The method gives quantitative information on the muscular stiffness and it can be used when estimating the time of death.     

Determination of Adenosine Phosphates in Rat Gastrocnemius at Various Postmortem Intervals Using High Performance Liquid Chromatography

Abstract: Although the change in adenosine phosphate levels in muscles may contribute to the development of rigor mortis, the relationship between their levels and the onset and development of rigor mortis has not been well elucidated. In the current study, levels of the adenosine phosphates including adenosine triphosphate (ATP), adenosine diphosphate (ADP), and adenosine monophosphate (AMP) in gastrocnemius at various postmortem intervals of 180 rats from different death modes were detected by high performance liquid chromatography. The results showed that the levels of ATP and ADP significantly decreased along with the postmortem period of rats from different death mode whereas the AMP level remained the same. In addition, it was found that changes in the ATP levels in muscles after death correlated well with the development of rigor mortis. Therefore, the ATP level could serve as a reference parameter for the deduction of rigor mortis in forensic science.     

Forced oral opening for cadavers with rigor mortis: two approaches for the myotomy on the temporal muscles

Forensic dentistry plays an essential role in personal identification procedures. An adequate interincisal space of cadavers with rigor mortis is required to obtain detailed dental findings. We have developed intraoral and two directional approaches, for myotomy of the temporal muscles. The intraoral approach, in which the temporalis was dissected with scissors inserted via an intraoral incision, was adopted for elderly cadavers, females and emaciated or exhausted bodies, and had a merit of no incision on the face. The two directional approach, in which myotomy was performed with thread-wire saw from behind and with scissors via the intraoral incision, was designed for male muscular youths. Both approaches were effective to obtain a desired degree of an interincisal opening without facial damage.     

Estimation of the breaking of rigor mortis by myotonometry

Myotonometry was used to detect breaking of rigor mortis. The myotonometer is a new instrument which measures the decaying oscillations of a muscle after a brief mechanical impact. The method gives two numerical parameters for rigor mortis, namely the period and decrement of the oscillations, both of which depend on the time period elapsed after death. In the case of breaking the rigor mortis by muscle lengthening, both the oscillation period and decrement decreased, whereas, shortening the muscle caused the opposite changes. Fourteen h after breaking the stiffness characteristics of the right and left m. biceps brachii, or oscillation periods, were assimilated. However, the values for decrement of the muscle, reflecting the dissipation of mechanical energy, maintained their differences.     

Postmortem changes in the level of calcium pumping adenosine triphosphatase in rat heart sarcoplasmic reticulum

The activity of calcium pumping adenosine triphosphatase (Ca2+-ATPase) in cardiac sarcoplasmic reticulum plays a pivotal role in myocardiac contraction-relaxation. The Ca2+-ATPase activity is controlled by phosphorylation and dephosphorylation of a sarcoplasmic reticulum protein "phospholamban" in response to neurotransmitters and drugs. To clarify the role of Ca2+-ATPase in the development of cardiac rigor mortis, we examined the changes of cardiac rigidity and cardiac sarcoplasmic reticulum Ca2+-ATPase activity up to 5 h after the decapitation of rats. Fifteen minutes after decapitation, the rats showed a cardiac rigidity on left ventricles. After 30 min, rigidity was obvious over the whole heart. After 1 h, the rigidity reached a high degree which was maintained for the rest of the observation period. On the other hand, the Ca2+-ATPase activity controlled by phosphorylation and dephosphorylation of phospholamban did not change for the whole observation period (5 h). Another Ca2+-ATPase activity representing the total amount of Ca2+-ATPase in sarcoplasmic reticulum gradually decreased. The data suggest that no significant phosphorylation or dephosphorylation of phospholamban occurs for a short time, at least for 5 h, after death and that the Ca2+-ATPase tends to relax the myocardium against the development of cardiac rigor mortis.     

Reconsideration of the sequence of rigor mortis through postmortem changes in adenosine nucleotides and lactic acid in different rat muscles

We examined the changes in adenosine triphosphate (ATP), lactic acid, adenosine diphosphate (ADP) and adenosine monophosphate (AMP) in five different rat muscles after death. Rigor mortis has been thought to occur simultaneously in dead muscles and hence to start in small muscles sooner than in large muscles. In this study we found that the rate of decrease in ATP was significantly different in each muscle. The greatest drop in ATP was observed in the masseter muscle. These findings contradict the conventional theory of rigor mortis. Similarly, the rates of change in ADP and lactic acid, which are thought to be related to the consumption or production of ATP, were different in each muscle. However, the rate of change of AMP was the same in each muscle.     

Mapping the lateral extent of human cadaver decomposition with soil chemistry

Soil below decomposing cadavers may have a different lateral spatial extent depending upon whether scavengers have access to the human cadaver or not. We examined the lateral spatial extent of decomposition products to a depth of 7cm of soils beneath two decomposing corpses, one in which the subject was autopsied, unclothed and placed under a wire cage to restrict scavenger access and one in which the subject was not autopsied, unclothed and exposed to scavengers. The two bodies had accumulated degree days (ADD) of 5799 and 5469 and post mortem interval (PMI) of 288 and 248d, respectively. The spatial extent for dissolved organic carbon (DOC) and organic nitrogen (DON) for both bodies was large but similar suggesting some movement off site for both compounds. Mean DOC was 1087±727 and 1484±1236μgg(-1) dry soil under the two corpses relative to 150±68μgg(-1) in upslope control soils. Sulfate tended to have 'hot spots' of lower values relative to the control soils indicative of anaerobic respiration. pH was lower and electrical conductivity was higher in the soil under both decomposing cadavers relative to control soils. Some of the nutrients examined downslope of the human remains were significantly higher than control soils upslope suggesting movement of decomposition products off-site which could be an important factor when using human remains detector dogs.     

Delimitation of the time of death by immunohistochemical detection of glucagon in pancreatic alpha-cells.

To improve the possibilities of delimitating the time of death after longer laytime it was examined if this is possible by immunohistochemical glucagon detection. The results show that in our examination material the pancreatic alpha-cells of up to 6-day-old corpses produce a positive immunoreaction towards glucagon in all cases whereas none of the corpses older than 14 days show such a reaction. This means that in the case of a negative immunoreaction the time of death can be assumed to lie more than 7 days before the autopsy. The fact that a negative immunoreaction occurs consistently after 14 days leads to the conclusion that when glucagon has been stained in a specimen, the death of the respective person must lie a maximum of 13 days earlier, whereby under markedly different conditions to the ones of the cases here examined, a negative immunoreaction could happen earlier and a positive immunoreaction even later.     

Death in a tetany attack

A case of latent tetany in a 24-year-old woman is reported. She had suffered several attacks of tetany in the last 12 years, mostly triggered by external stimuli. One evening, the woman was found dead in the hall of her flat beside the telephone with the upper limbs in a tetanic convulsive attitude. The attack of tetany was triggered by a telephone conversation. The parathyroid glands were normal. Day-old purulent myocarditis could be demonstrated in the left ventricle under the light microscope. The two possible pathogenetic explanations of the causal chain leading to death are discussed. It was astonishing that a clinical symptom (tetanic convulsion) was fixed in rigor mortis.     

Postmortem production of ethanol in different tissues under controlled experimental conditions

The aim of this study was to follow the postmortem ethanol production phenomenon under controlled experimental conditions (temperature, time interval) in different tissues. Specimens of blood, liver, skeletal muscle and kidney were taken from 30 corpses and no chemical preservatives were used in the specimens collected. Ethanol concentrations were detected by gas chromatography. All specimens stored at -20 degrees C and 4 degrees C did not show any change in ethanol concentration in an eight-day time interval. At 20 degrees C and 30 degrees C, all tissues, except blood, showed statistically significant ethanol production over the time interval tested. However, blood sample kept at 30 degrees C, showed statistically significant increase in ethanol production on the 2nd and 4th day comparing to the controls. Thus, we can state that postmortem ethanol production occurs in different tissues, and is increased at higher temperatures and, in general, it is in accordance with the course of time.     

The determination of CK,LDH and its isoenzymes in pericardial fluid and its application to the post-mortem diagnosis of myocardial infarction

After having studied 144 pericardial fluids, from the same number of judicial corpses, we propose the measurement of CK for the postmortem diagnosis of myocardial infarction, since it is a reliable, exact and easy technique available to an ordinary laboratory. Providing that contaminated samples be disregarded, the fluids are centrifuged early, and the cadavers be under 48 hours old, the study of CK enzymatic levels in the pericardial fluid allows the postmortem differentiation of myocardial infarction from other causes of death.     

Autolytic changes in blood cells of human cadavers. II. Morphological studies

The morphology of various types of cells in the peripheral blood of human cadavers was investigated. The material comprised 123 medicolegal autopsy cases with post-mortem (p.m.) times ranging from 1.7 to 270.4 hours. The corpses were kept at +4 °C. The haematocrit values of the blood increased rapidly after death. The haematocrit-corrected red cell count, and the total white cell and platelet counts remained quite stable during the whole p.m. time range. Red cells were quite rapidly transformed from a discoid configuration to crumbled discs, echinocytes and spherocytes, but no debris or burst cell configurations were seen. Rapid deterioration of the staining properties and marked morphological changes in many leucocytes occurred quite rapidly after death. Lymphocytes seemed to be the most resistant and basophils the least resistant to the effects of autolysis. Morphologically altered platelets and aggregates of them were seen in each cadaver.The present morphological observations and the quantitative results suggest that various cellular elements of the blood seem to be quite resistant to autolytic effects, and many cells apparently retain their viability for longer periods of time in the blood of cadavers kept at reduced temperature.