Rigor mortis

A i.e. 2 – 3 hours

A i.e. 24 – 48 hours

C i.e. Stiffens & shorten

In rigor mortis, muscle shorten (contracted) & stiffensQ, and the reaction changes from alkaline to distinctly acidic d/t local formation of lactic acid.

A i.e. Heat stiffness; B i.e. Cold stiffness

A i.e. Cadaveric spasm

C i.e. Arsenic

Ans: D i.e. Toes

Rigor mortis first appears in the involuntary muscles; the myocardium.

It begins in eyelids, neck and lower jaw and passes upwards to the muscle of the face, and downwards to the muscles of the chest, upper limbs, abdomen and lower limbs and lastly in the finger and toes

Ans. C: Muscle of the body began to stiffen

The phenomenon is caused by the skeletal muscles partially contracting. The muscles are unable to relax, so the joints become fixed in place Rigor mortis can be used to help estimate time of death.

The onset of rigor mortis may range from 1-2 hours, depending on factors including temperature (rapid cooling of a body can inhibit rigor mortis, but it occurs upon thawing). Maximum stiffness is reached around 12-24 hours post mortem. It first starts in involuntary muscles (myocardium)

Eyelids, neck and jaw muscles are affected first, with the rigor then spreading to other parts of the body.

The joints are stiff but after some time general tissue decay and leaking of lysosomal intracellular digestive enzymes will cause the muscles to relax.

Ans. Seen immediately after death

Ans. 10-12 h

Ans. Heart

Ans. Muscles of eyelids

Ans. Pneumonia

Ans. Fetus < 7 months of fetus

Rigor mortis may not be seen in infant

Rigor mortis does not develop in a fetus of < 7 months of intrauterine age. It is moderate in children, emaciated and in elderly people. 

Ans. Tetanus

Ans. is ‘c’ i.e., Cadaveric spasm

• Cadaveric spasm (instantaneous rigor) is defined as the condition wherein a group of muscles, which were in contraction or spasm at the time of death, continue to be in spasm even after death, without the stage of primary relaxation.

• It is a condition in which the muscles of the body which were in a state of contraction immediately before death, continue to be so after death without passing through the stage of primary relaxation. 

• Cadaveric spasm, being an antemortem phenomenon, reflects the last act of the subject performed before and at the time of his death. The cause and manner of death may be judged. 

• It may be due to exhausted ATP in the affected muscles with the persistence of contraction even after death and the resulting failure of the chemical processes required for active muscular relaxation to occur during molecular death. Adrenocortical exhaustion, which impairs resynthesis of ATP may be the possible cause 

Ans. is ‘a’ i.e., Dead born

Signs of dead born (intrauterine death : IUD) are (i) Rigor mortis at birth, (ii) Maceration, (iii)Putrefaction, and (iv) Mummification.

Ans. is ‘b’ i.e., Later than expected

• In temperate climate, rigor mortis begins late and lasts longer than in tropical countries.

Rigor mortis (Cadaveric Rigidity or Death Stiffening)

• It is defined as contraction, stiffening, shortenig and opacity of muscles after death. It occurs after molecular (cellular) death.
• In tropical countries (e.g. india), it begins 1-2 hours after death, takes further 2 hours to develop, and lasts for 18-36 hours in summer and 24-48 hours in winter. In temperate countries, it begins in 3-6 hours, takes further 2­3 hours to develop and lasts for 2-3 days.
• All muscles of body are involved, i.e. voluntary or involuntary.
• However, it does not start in all muscles simultaneously (nysten’s rule). Involuntary muscles (heart) are involved first than voluntary muscles. Sequence of muscles involvement is as follows : Heart> upper eyelid> neck >jaw > face > chest > upper limb > abdomen > lower limb > finger and toes.
• It passes off in the same order in which it has appeared.
• Factors affecting rigor mortis

1. Rigor mortis is not seen : (1) Fetus < 7 months, (ii) Septiccemic conditions.
2. Appears early and passes off quickly : (i) Chronic diseases (TB, cancer, typhoid, cholera), (ii) Convulsive disorders (strychnine poisoning ), (iii) Violent deaths (cut throat, electrocution, lightening).
3. Early onset and last longer : Drowning and strychnine poisoning
4. Early onset : Organophosphate poisoning and fatigue/exhaustion before death
5. Delayed onset : Asphyxia, apoplexy, severe hemorrhage, pneumonia and paralysis of muscles.
6. Lasts longer or delayed disappearance : (i) CO poisoning, (ii) Arsenic poisoning
7. Early disappearance : Widespread bacterial infection, e.g., gas gangrene.