Understanding Rigor Mortis: Mechanism, Causes, And Timeline

Understanding Rigor Mortis: Mechanism, Causes, And Timeline

Rigor mortis.
Answer:

• It refers to after death condition of the body which is characterized by stiffness of muscles and joints.
• It is derived from Latin word ‘rigor’ means ‘stiff’

Rigor mortis Mechanism:

• Soon after death, the cell membrane becomes highly permeable to calcium.
• As a result there is excessive influx of calcium into muscle which promotes the formation of actinomyosin complex.
• This causes contraction of muscles.
• Due to repeated contraction, the muscles become stiff after few hours of death.

Rigor mortis Cause:

• Normally, muscle contraction is compensated by relaxation.
• But for relaxation muscle needs ATP which causes exit of calcium.
• After death, due to repeated and excessive muscle contraction all ATP is used up and gets exhausted.
• Even new ATP cannot be produced due to lack of oxygen.
• As a result, the muscle remain in contracted state.

Rigor mortis Importance:

• Rigor mortis is important medico legally.
• It determines the time of death.
• Onset of stiffness start between 10 min and 3 hours after death.
• This depends on condition of the body and environmental temperature at the time of death.
• If body is active and temperature is high, stiffness occurs quickly.
• Stiffness occurs first in facial muscle and then spreads to other parts.
• Maximum stiffness occurs around 12-24 hours after death and remains for 1-3 days.