Forensic Medicine 2: Time of Death and Postmortem Changes

Flashcards covering muscle changes, blood changes, stages of decomposition, and methods for determining the duration of death based on forensic medicine lecture notes.

Stage of Primary flaccidity

The period of muscular irritability occurring immediately after death, lasting 3-6 hours (or approximately 1 hour and 51 minutes in warm places), where muscles remain contractile with stimuli.

Post-mortem rigidity (Rigor mortis)

The gradual stiffening of all muscles (voluntary and involuntary) beginning 3-6 hours after death, usually starting at the neck and lower jaw and spreading downwards.

Chemical reaction of Rigor mortis

The change in muscle reaction to acidic due to an increase in lactic acid and phosphoric content.

Heat Stiffening

The coagulation of muscle proteins causing permanent rigidity when a dead body is exposed to temperatures above $75^{\circ}\text{C}$, often resulting in a pugilistic attitude.

Pugilistic Attitude

A stance commonly observed in bodies burned to death where upper and lower extremities are flexed and hands are clenched because flexor muscles are stronger than extensors.

Cold Stiffening

Stiffening of the body due to the solidification of fat when exposed to freezing temperatures, which disappears when the body is moved to warm conditions.

Cadaveric spasm

Instantaneous rigidity of muscles occurring at the moment of death due to extreme tension, exhaustion, or injury to the nervous system, often causing a weapon to be held tightly.

Secondary Flaccidity

The stage of secondary relaxation following the disappearance of rigor mortis, marking the onset of decomposition and non-responsiveness to stimuli.

Clostridium welchii (perfringens)

The usual microorganism seen during the process of decomposition and putrefaction.

Post-mortem Lividity (Livor Mortis)

The accumulation of blood in the most dependent portions of the body, appearing dull-red or purplish 3-6 hours after death and peaking at 12 hours.

Hypostatic Lividity

A form of post-mortem lividity where blood gravitates to dependent portions while still inside the blood vessels in fluid form.

Diffusion Lividity

A later stage of post-mortem lividity that appears once blood has coagulated inside the blood vessels.

Bright pink lividity

The color of post-mortem lividity characteristic of death caused by Carbon Monoxide poisoning.

Chocolate or Coffee colored lividity

The color of post-mortem lividity indicating death caused by Potassium chlorate or Potassium dichromate.

Autolysis

The autodigestion of organs after death caused by the continued action of proteolytic, glycolytic, and lipolytic ferments of glandular tissue.

Putrefaction

The breakdown of complex proteins into simpler components, accompanied by foul-smelling gases and changes in body color.

Marbolization

The prominence of superficial veins with reddish discoloration during decomposition resulting from bacteria-induced hemolysis.

Greenish discoloration of the right iliac fossa

The earliest change in tissue color during putrefaction, beginning at the lower right quadrant of the abdominal wall.

Highly muscular organs (Putrefaction rate)

Tissues and organs that are known to putrefy relatively late compared to other soft tissues.

Mummification

A special modification of putrefaction involving the dehydration of the whole body, leading to shivering and preservation.

Saponification (Adipocere Formation)

The transformation of fatty tissues into a soft, brownish-white, waxy, and greasy substance with a rancid or moldy odor.

Maceration

The softening of tissues in a fluid medium in the absence of putrefactive microorganisms, frequently observed in fetal death in utero.

Entomology of the Cadaver

A method to approximate time of death; the presence of moving maggots indicates death occurred more than 24 hours ago, as eggs hatch into larvae in 24 hours.

Stage of Digestion

A metric for determining duration of death; normally, it takes 3-4 hours for the stomach to evacuate its contents after a meal.

Cerebrospinal Fluid (CSF) post-mortem changes

Chemical changes after death including an increase in lactic acid, non-protein nitrogen, and amino-acid concentration.