Zsako Phenomenon

 

The "Zsako phenomenon," also known as idiomuscular contraction following mechanical stimulation, refers to the contraction of skeletal muscle fibers in response to a mechanical stimulus, even after death. 

This phenomenon is observable within the first few hours after death and can be used as a post-mortem indicator. 

Mechanical Excitability:

Skeletal muscles, when stimulated mechanically (e.g., by a tap on the tendon), can contract even after death due to the excitability of the muscle fibers. 

Propagation of Excitation:

This phenomenon involves the propagation of excitation along the muscle fibers, leading to a visible contraction of the muscle. 

Time Frame:

Zsako's phenomenon is typically observed within the first 2-3 hours after death, although localized contractions can sometimes be seen even later. 

Forensic Relevance:

This phenomenon is a valuable tool in forensic science for estimating the time of death, particularly in the early post-mortem period. 

                                                     Snapshot

                                     1.5–2.5 hours postmortem

                                                 Zsako's muscle phenomenon

                             Mechanical stimulation causes propagated excitation