Rigor mortis - wikipedia Rigor mortis This article is about the sign of death. For other uses, see Rigor mortis ( disambiguation ). Stages of death Pallor mortis Algor mortis Rigor mortis Livor mortis Putrefaction Decomposition Skeletonization Fossilization Rigor mortis ( Latin : rigor `` stiffness '', mortis `` of death '' ), the third stage of death, is one of the recognizable signs of death, caused by chemical changes in the muscles post mortem, which cause the limbs of the corpse to stiffen. In humans, rigor mortis can occur as soon as 4 hours post mortem. Contents 1 Physiology 2 Physical changes 3 Applications in meat industry 4 Application in forensic pathology 5 See also 6 References 7 Bibliography Physiology After death, respiration in an organism ceases, depleting the source of oxygen used in the making of adenosine triphosphate ( ATP ). ATP is required to cause separation of the actin - myosin cross-bridges during relaxation of muscle. When oxygen is no longer present, the body may continue to produce ATP via anaerobic glycolysis. When the body 's glycogen is depleted, the ATP concentration diminishes, and the body enters rigor mortis because it is unable to break those bridges. Additionally, calcium enters the cytosol after death. Calcium is released into the cytosol due to the deterioration of the sarcoplasmic reticulum. Also, the breakdown of the sarcolemma causes additional calcium to enter the cytosol. The calcium activates the formation of actin - myosin cross-bridging. Once calcium is introduced into the cytosol, it binds to the troponin of thin filaments, which causes the troponin - tropomyosin complex to change shape and allow the myosin heads to bind to the active sites of actin proteins. In rigor mortis myosin heads continue binding with the active sites of actin proteins via adenosine diphosphate ( ADP ), and the muscle is unable to relax until further enzyme activity degrades the complex. Normal relaxation would occur by replacing ADP with ATP, which would destabilize the myosin - actin bond and break the cross-bridge. However, as ATP is absent, there must be a breakdown of muscle tissue by enzymes ( endogenous or bacterial ) during decomposition. As part of the process of decomposition, the myosin heads are degraded by the enzymes, allowing the muscle contraction to release and the body to relax. Decomposition of the myofilaments occurs 48 to 60 hours after the peak of rigor mortis, which occurs approximately 13 hours after death. Physical Changes At the time of death, a condition called `` primary flaccidity '' occurs. Following this, the muscles stiffen in rigor mortis. All muscles in the body are affected. Starting between two and six hours following death, rigor mortis begins with the eyelids, neck, and jaw. The sequence may be due to different lactic acid levels among different muscles, which is directly related to the difference in glycogen levels and different types of muscle fibers. Rigor mortis then spreads to the other muscles, including the internal organs, within the next four to six hours. The onset of rigor mortis is affected by the individual 's age, sex, physical condition, and muscular build. Rigor mortis may not be perceivable in many infant and child corpses due to their smaller muscle mass. Applications in meat industry Rigor mortis is very important in meat technology. The onset of rigor mortis and its resolution partially determine the tenderness of meat. If the post-slaughter meat is immediately chilled to 15 ° C ( 59 ° F ), a phenomenon known as cold shortening occurs, whereby the muscle sarcomeres shrink to a third of their original length. Cold shortening is caused by the release of stored calcium ions from the sarcoplasmic reticulum of muscle fibers, in response to the cold stimulus. The calcium ions trigger powerful muscle contraction aided by ATP molecules. To prevent cold shortening, a process known as electrical stimulation is carried out, especially in beef carcasses, immediately after slaughter and skinning. In this process, the carcass is stimulated with alternating current, causing it to contract and relax, which depletes the ATP reserve from the carcass and prevents cold shortening. Application in forensic pathology The degree of rigor mortis may be used in forensic pathology, to determine the approximate time of death. A dead body holds its position as rigor mortis sets in. If the body is moved after death, but before rigor mortis begins, forensic techniques such as livor mortis can be applied. If the position in which a body is found does not match the location where it is found ( for example, if it is flat on its back with one arm sticking straight up ), that could mean someone moved it. Several factors also affect the progression of rigor mortis, and investigators take these into account when estimating the time of death. One such factor is the ambient temperature. When conditions are warm, the onset and pace of rigor mortis are sped up by providing a conducive environment for the metabolic processes that cause decay. Low temperatures, however, slow them down. Therefore, for a person who dies outside in frozen conditions rigor mortis may last several days more than normal, so investigators may have to abandon it as a tool for determining time of death. See also Cadaveric spasm References ^ Jump up to : Saladin, K.S. 2010. Anatomy & Physiology : 6th edition. McGraw - Hill. ^ Jump up to : Hall, John E., and Arthur C. Guyton. Guyton and Hall Textbook of Medical Physiology. Philadelphia, PA : Saunders / Elsevier, 2011. MD Consult. Web. 26 Jan. 2015. Jump up ^ Fremery, Donald ( 3 February 1959 ). `` Biochemistry of Chicken Muscle as Related to Rigor Mortis and Tenderization ''. Journal of Food Sciences. 25 ( 1 ) : 73 -- 87. doi : 10.1111 / j. 1365 - 2621.1960. tb17938. x. Retrieved 2 December 2015. Jump up ^ About.com Jump up ^ `` Classroom Resources - Argonne National Laboratory ''. Jump up ^ `` Rigor Mortis and Other Postmortem Changes - Burial, Body, Life, Cause, Time, Person, Human, Putrefaction. '' Encyclopedia of Death and Dying. 2011. Web. 4 December 2011. < http://www.deathreference.com/Py-Se/Rigor-Mortis-and-Other-Postmortem-Changes.html >. Jump up ^ `` New Zealand Journal of Agricultural Research ''. Jump up ^ Peress, Robin. `` Discovery Health `` Rigor Mortis at the Crime Scene '' '' Discovery Health `` Health Guides '' Discovery Fit & Health, 2011. Web. 4 December 2011. < http://health.howstuffworks.com/diseases-conditions/death-dying/rigor-mortis-cause2.htm > Jump up ^ Estimating The Time of Death, ExploreForensics < http://www.exploreforensics.co.uk/estimating-the-time-of-death.html Bibliography Bear, Mark F ; Connors, Barry W. ; Paradiso, Michael A., Neuroscience, Exploring the Brain, Philadelphia : Lippincott Williams & Wilkins ; Third Edition ( 1 February 2006 ). ISBN 0 - 7817 - 6003 - 8 Robert G. Mayer, `` Embalming : history, theory, and practice '', McGraw - Hill Professional, 2005, ISBN 0 - 07 - 143950 - 1 `` Rigor Mortis and Other Postmortem Changes - Burial, Body, Life, Cause, Time, Person, Human, Putrefaction. '' Encyclopedia of Death and Dying. 2011. Web. 4 December 2011. < http://www.deathreference.com/Py-Se/Rigor-Mortis-and-Other-Postmortem-Changes.html >. Saladin, Kenneth. Anatomy and Physiology : The Unity of Form and Function, 6th ed. McGraw - Hill. New York, 2012. Peress, Robin. `` Discovery Health `` Rigor Mortis at the Crime Scene '' '' Discovery Health `` Health Guides '' Discovery Fit & Health, 2011. Web. 4 December 2011. < http://health.howstuffworks.com/diseases-conditions/death-dying/rigor-mortis-cause2.htm >. Death Outline In medicine Cell death Necrosis Avascular necrosis Coagulative necrosis Liquefactive necrosis Gangrenous necrosis Caseous necrosis Fat necrosis Fibrinoid necrosis Temporal lobe necrosis Programmed cell death AICD Anoikis Apoptosis Autophagy Intrinsic apoptosis Necroptosis Paraptosis Parthanatos Phenoptosis Pseudoapoptosis Pyroptosis Autolysis Autoschizis Eschar Immunogenic cell death Ischemic cell death Pyknosis Karyorrhexis Karyolysis Mitotic catastrophe Suicide gene Abortion Autopsy Brain death Brainstem death Clinical death DOA Death by natural causes Death rattle Dysthanasia End - of - life care Euthanasia Lazarus sign Lazarus syndrome Medical definition of death Organ donation Terminal illness Unnatural death Lists Causes of death by rate Expressions related to death Natural disasters People by cause of death Premature obituaries Preventable causes of death Notable deaths by year Unusual deaths TV actors who died during production Mortality Birthday effect Child mortality Gompertz -- Makeham law of mortality Immortality Biological Digital Infant mortality Karōshi Maternal death Maternal mortality in fiction Memento mori Micromort Mortality displacement Mortality rate RAMR Mortality salience Perinatal mortality After death Body Stages Pallor mortis Algor mortis Rigor mortis Livor mortis Putrefaction Decomposition Skeletonization Fossilization Preservation Cryopreservation Cryonics Neuropreservation Embalming Maceration Mummification Plastination Prosection Taxidermy Disposal Burial Bed burial Burial at sea Chariot burial Jar burial Natural burial Premature burial Secondary burial Ship burial Sky burial Space burial Cannibalism Cremation Dismemberment Excarnation Promession Resomation Beating heart cadaver Body donation Cadaveric spasm Coffin birth Death erection Dissection Gibbeting Postmortem Caloricity Post-mortem interval Other aspects Afterlife Cemetery Consciousness Customs Death mask Eternal oblivion Examination Funeral Grief Intermediate state Internet Mourning Obituary Resurrection Taboo on the dead Vigil Paranormal Ghosts Near - death experience Near - death studies Necromancy Out - of - body experience Reincarnation research Séance Legal Abortion law Administration Capital punishment Cause of death Civil death Coroner Death - qualified jury Death certificate Declared death in absentia Death row Dying declaration Faked death Inquest Legal death Murder Prohibition of death Right to die Suspicious death Trust law Will Fields Forensic pathology Funeral director Mortuary science Necrobiology Post-mortem chemistry Post-mortem photography Taphonomy Biostratinomy Thanatology Other Apparent death Dark tourism Darwin Awards Dead pool Death and culture Death anniversary Death anxiety Death deity Personification of death Dying - and - rising god Psychopomp Death camp Death drive Death education Death from laughter Death hoax Death knell Death march Death messenger Death notification Death panel Death poem Death pose Death squad Death threat Death trajectory Dignified death Extinction Fan death Festival of the Dead Fascination with death Homicide Information - theoretic death Last rites Martyr Megadeath Museum of Death Necronym Necrophilia Necrophobia The Order of the Good Death Predation Sacrifice human animal Spiritual death Suicide Assisted suicide Thanatosensitivity Undead Voodoo death Portal WikiProject Retrieved from `` https://en.wikipedia.org/w/index.php?title=Rigor_mortis&oldid=805511783 '' Categories : Signs of death Latin medical phrases Medical aspects of death Forensic pathology Hidden categories : Use dmy dates from April 2012 Talk Contents About Wikipedia Български Català Čeština Deutsch Español فارسی Français Gaeilge हिन्दी Bahasa Indonesia Italiano עברית Қазақша Magyar മലയാളം Nederlands 日本 語 Norsk ਪੰਜਾਬੀ Polski Português Română Русский Simple English Српски / srpski Srpskohrvatski / српскохрватски Suomi Svenska தமிழ் ไทย Türkçe Українська Tiếng Việt 中文 Edit links This page was last edited on 15 October 2017, at 21 : 43. 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Question: when does rigor mortis set in in humans
Answer: as soon as 4 hours post mortem