Detailed Presentation on Rigor mortis From medical and medico legal point of view

2. Rigor Mortis
By: Imtiaz ur Rehman
4th Year MBBS
Khyber Medical College Peshawar

3. Definition
• Rigor Mortis is normal muscle contraction that occurs after death and is
fixed due to lack of ATP

4. Mechanism of Rigor
Mortis

10. Characteristics
• Occurs in both involuntary and voluntary muscles
• Appears first in short muscles and then in larger muscles
• It has nothing to do with nerve supply as it can occur in paralyzed limbs as well
• Muscle become brittle and tearable
• Heart will be in permanent contracted state and will contain very little blood
• Skin will have granular appearance due to contraction of Erector Pilae muscles. This condition is called
Cutis Ansernia or goose skin
• Discharge of semen due to involvement of seminal vesicles
• Iris will contract abnormally
• Post mortem delivery

11. Progression of Rigor Mortis
Eyelid
3-4 hrs
Face
4-5 hrs
Neck &
Trunk
5-7 hrs
Upper
Limb
7-9 hrs
Lower
Limb
9-11 hrs
Small Muscles
of fingers &
toes
11-12 hrs
Static
phase
13-24 hrs
Passing off
phase
25-48 hrs
Proximodistal Progression
(Nysten’s Law)

12. Testing of Rigor Mortis
• Attempting to open eyelid
• Depressing the jaw
• Flexing neck and other joints

13. Factors effecting Rigor Mortis
• Temperature
• Age
• Body structure
• Nutritional status
• Muscular activity
• Mode of death

14. Medicolegal importance
• Diagnosis of death
• Determining postmortem interval
• Determining manner of death
• Position of body at the time of death

15. • Postmortem
• Involves both voluntary as well as
involuntary muscles
• Muscles of whole body are affected
• Has a specific pattern of development
• Occurs in all deaths
• Moderate force is required to break the
rigidity
• Has no relation to establishment of manner
of death
• Antemortem
• Involves only voluntary muscles
• Only a group of muscles is effected
• Develops instantaneously, being
associated with last action before death
• Occurs in sudden death and emotional
stress
• Very hard to break
• Helps to establish manner of death
• Rigor Mortis • Cadaveric Spasm

16. Thanks!!!