Rigor Mortis

Name: Rigor Mortis
Uploaded: 2013-06-18T02:24:49.000Z
Duration: 4 min 8 s
Description: Beef Rigor Mortis This animation project was funded by the Beef Checkoff and done in collaboration with The Colorado State University Center for Meat Safety and Quality in the Dept of Animal Sciences. The Meat Safety and Quality team provided expert resources, project oversight and quality control, and animation materials during the development lifecycle.

Rigor Mortis: Understanding Postmortem Muscle Stiffening

What is Rigor Mortis?

Rigor mortis, derived from Latin meaning "stiffness of death," refers to the postmortem stiffening of muscles caused by the permanent formation of actomyosin crossbridges.

In living muscle contraction, relaxation occurs through the binding of magnesium and ATP; however, this process fails postmortem due to a lack of ATP.

Phases of Rigor Mortis

Delay Phase

The delay phase lasts approximately 6 to 12 hours postmortem, during which the formation of actomyosin crossbridges is temporarily delayed.

This delay is facilitated by creatine phosphate and glycogen stores in muscles that help rephosphorylate ADP to ATP, allowing for some muscle relaxation.

Onset Phase

As energy reserves diminish, the ability to break crossbridges decreases, leading to increased muscle stiffness.

During this phase, muscles become relatively inextensible as maximum tension is reached.

Key Insights on Muscle Binding

Nearly all possible binding sites form crossbridges during rigor mortis compared to only about 20% during normal muscle contraction.

Video description

Beef Rigor Mortis This animation project was funded by the Beef Checkoff and done in collaboration with The Colorado State University Center for Meat Safety and Quality in the Dept of Animal Sciences. The Meat Safety and Quality team provided expert resources, project oversight and quality control, and animation materials during the development lifecycle.