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At least 19 recordsLinked to original sources
PubMedDate not supplied

Experimental evaluation of rigor mortis. III. Comparative study of the evolution of rigor mortis in different sized muscle groups in rats.

The use of new methods and an appropriate apparatus has allowed us to make successive measurements of rigor mortis and a study of its evolution in the rat. By a comparative examination on the front and hind limbs, we have determined the following: (1) The muscular mass of the hind limbs is 2.89 times greater than that of the front limbs. (2) In the initial phase rigor mortis is more pronounced in the front limbs. (3) The front and hind limbs reach maximum rigor mortis at the same time and this state is maintained for 2 hours. (4) Resolution of rigor mortis is accelerated in the front limbs during the initial phase, but both front and hind limbs reach complete resolution at the same time.

Animals↗
PubMedDate not supplied

Experimental evaluation of rigor mortis. V. Effect of various temperatures on the evolution of rigor mortis.

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

Animals↗
PubMed1983

Experimental evaluation of rigor mortis. VI. Effect of various causes of death on the evolution of rigor mortis.

The evolution of rigor mortis was studied in cases of nitrogen asphyxia, drowning and strangulation, as well as in fatal intoxications due to strychnine, carbon monoxide and curariform drugs, using a modified method of measurement. Our experiments demonstrated that: (1) Strychnine intoxication hastens the onset and passing of rigor mortis. (2) CO intoxication delays the resolution of rigor mortis. (3) The intensity of rigor may vary depending upon the cause of death. (4) If the stage of rigidity is to be used to estimate the time of death, it is necessary: (a) to perform a succession of objective measurements of rigor mortis intensity; and (b) to verify the eventual presence of factors that could play a role in the modification of its development.

Airway Obstruction↗
PubMedDate not supplied

Experimental evaluation of rigor mortis. IV. Change in strength and evolution of rigor mortis in the case of physical exercise preceding death.

Evolution of rigor mortis in rats exercised before death shows the following characteristics with respect to controls: (1) Its intensity is increased in the initial phase. (2) It reaches its maximum development at the same time. (3) Higher maximum values are reached (in our experiments 1.39 times the maximum values for controls). (4) Higher values are maintained from 100 minutes to 16 hours with statistically significant differences. (5) It attains resolution at the same time.

Animals↗
PubMedDate not supplied

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.

Adult↗
PubMed1994

Experimental evaluation of rigor mortis. VIII. Estimation of time since death by repeated measurements of the intensity of rigor mortis on rats.

The development of the intensity of rigor mortis was monitored in nine groups of rats. The measurements were initiated after 2, 4, 5, 6, 8, 12, 15, 24, and 48 h post mortem (p.m.) and lasted 5-9 h, which ideally should correspond to the usual procedure after the discovery of a corpse. The experiments were carried out at an ambient temperature of 24 degrees C. Measurements initiated early after death resulted in curves with a rising portion, a plateau, and a descending slope. Delaying the initial measurement translated into shorter rising portions, and curves initiated 8 h p.m. or later are comprised of a plateau and/or a downward slope only. Three different phases were observed suggesting simple rules that can help estimate the time since death: (1) if an increase in intensity was found, the initial measurements were conducted not later than 5 h p.m.; (2) if only a decrease in intensity was observed, the initial measurements were conducted not earlier than 7 h p.m.; and (3) at 24 h p.m., the resolution is complete, and no further changes in intensity should occur. Our results clearly demonstrate that repeated measurements of the intensity of rigor mortis allow a more accurate estimation of the time since death of the experimental animals than the single measurement method used earlier. A critical review of the literature on the estimation of time since death on the basis of objective measurements of the intensity of rigor mortis is also presented.

Animals↗
PubMed1993

Rigor or rigor mortis: the problem of rigor in qualitative research revisited.

Issues are raised by the persistent concern with achieving rigor in qualitative research, including the rigidity that often characterizes the search for validity in qualitative work and the threat to validity that the search for reliability may pose. Member validation is highlighted as a technique that exemplifies not only the practical, but also the profoundly theoretical, representational, and even moral problems raised by all procedures aimed at ensuring the trustworthiness of qualitative work.

Attitude of Health Personnel↗
PubMed1978

Studies on the estimation of the postmortem interval. 3. Rigor mortis (author's transl).

The authors have devised a method for classifying rigor mortis into 10 types based on its appearance and strength in various parts of a cadaver. By applying the method to the findings of 436 cadavers which were subjected to medico-legal autopsies in our laboratory during the last 10 years, it has been demonstrated that the classifying method is effective for analyzing the phenomenon of onset, persistence and disappearance of rigor mortis statistically. The investigation of the relationship between each type of rigor mortis and the postmortem interval has demonstrated that rigor mortis may be utilized as a basis for estimating the postmortem interval but the values have greater deviation than those described in current textbooks.

Adolescent↗
PubMed1979

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.

Cadaver↗
PubMed1996

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.

Data Interpretation, Statistical↗
PubMed1977

[A new formula for the measurement of rigor mortis: the determination of the FRR-index (author's transl)].

The manual examination of rigor mortis as currently used and its often subjective evaluation frequently produced highly incorrect deductions. It is therefore desirable that such inaccuracies should be replaced by the objective measuring of rigor mortis at the extremities. To that purpose a method is described which can also be applied in on-the-spot investigations and a new formula for the determination of rigor mortis--indices (FRR) is introduced.

Arm↗
PubMed1992

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.

Death↗
PubMed1978

The effect of rigor mortis on the passage of erythrocytes and fluid through the myocardium of isolated dog hearts.

The effect of normal and artificially induced rigor mortis on the vascular passage of erythrocytes and fluid through isolated dog hearts was studied. Increased rigidity of 6-mm thick transmural sections through the centre of the posterior papillary muscle was used as an indication of rigor. The perfusibility of the myocardium was tested by injecting 10 ml of 1% sodium fluorescein in Hanks solution into the circumflex branch of the left coronary artery. In prerigor hearts (20 minute incubation) fluorescein perfused the myocardium evenly whether or not it was preceded by an injection of 10 ml of heparinized dog blood. Rigor mortis developed in all hearts after 90 minutes incubation or within 20 minutes of perfusing the heart with 50 ml of 5 mM iodoacetate in Hanks solution. Fluorescein injected into hearts in rigor did not enter the posterior papillary muscle and adjacent subendocardium whether or not it was preceded by heparinized blood. Thus the vascular occlusion caused by rigor in the dog heart appears to be so effective that it prevents flow into the subendocardium of small soluble ions such as fluorescein.

Animals↗
PubMedDate not supplied

An ultramicroscopic study on rigor mortis.

Gastrocnemius muscles taken from decapitated mice at various intervals after death and from mice killed by 2,4-dinitrophenol or mono-iodoacetic acid injection to induce rigor mortis soon after death, were observed by electron microscopy. The prominent appearance of many fine cross striations in the myofibrils (occurring about every 400 A) was considered to be characteristic of rigor mortis. These striations were caused by minute granules studded along the surfaces of both thick and thin filaments and appeared to be the bridges connecting the 2 kinds of filaments and accounted for the hardness and rigidity of the muscle.

Animals↗
PubMed1989

[Micromorphology of rigor mortis in human skeletal muscle].

Following our examination on rat muscle, it was investigated, whether alterations, observed in semi thin sections and by TEM could be used for forensic purposes. Investigated were extension of stiffened muscles. Samples of various muscle groups were taken at different time intervals before and after breaking the rigor muscle fibers. They were examined by light and electron microscopy. Results on the development and spontaneous disappearance of rigor mortis during the early and intermediate post mortem period are almost equivalent to those found by experiments on animals. Results concerning the breaking of rigor mortis, however, are sometimes considerably more discrete and diverge substantially. Because of artifacts, especially during the transport of the corpse, the interpretation is more difficult. The use of other techniques combined with drawing out muscle samples immediately at the place, where the corpse is found, may optimize the results.

Humans↗
PubMed1981

Changes in the contractile state, fine structure and metabolism of cardiac muscle cells during the development of rigor mortis.

Transmural slices from the left anterior papillary muscle of dog hearts were maintained for 120 min in a moist atmosphere at 37 degrees C. At 15-min intervals tissue samples were taken for estimation of adenosine triphosphate (ATP) and glucose-6-phosphate (G6P) and for electron microscopic examination. At the same time the deformability under standard load of comparable regions of an adjacent slice of tissue was measured. ATP levels fell rapidly during the first 45 to 75 min after excision of the heart. During a subsequent further decline in ATP, the mean deformability of myocardium fell from 30 to 12% indicating the development of rigor mortis. Conversely, G6P levels increased during the first decline in adenosine triphosphate but remained relatively steady thereafter. Whereas many of the myocardial cells fixed after 5 min contracted on contact with glutaraldehyde, all cells examined after 15 to 40 min were relaxed. A progressive increase in the proportion of contracted cells was observed during the rapid increase in myocardial rigidity. During this late contraction the cells showed morphological evidence of irreversible injury. These findings suggest that ischaemic myocytes contract just before actin and myosin become strongly linked to maintain the state of rigor mortis.

Adenosine Triphosphate↗
PubMed1977

[Measurements of rigor mortis on human skeletal muscles in situ (author's transl)].

The torque, necessary to break the rigor mortis of arms and legs at 17 female and 35 male cadavers stored at a temperature of 4 degrees C was determined. The values show differences between male and female cadavers to an extent, that both groups have to be treated separately. Relating the torque to the diameter or the cross section of the limb does not eliminate the differences: Frequently considerable differences between left and right limbs were obtained, however, without preference of one side over the other. There is no direct functional relationship between post mortem time and the intensity of r.m., but the values occasionally allow estimates on the maximum time post mortem.

Adolescent↗