The myth that hair continues to grow after death has intrigued humanity for centuries. This belief, often bolstered by anecdotal evidence and historical accounts, has found its way into literature, folklore, and even modern media. However, a scientific understanding of changes post-mortem challenges these myths, shedding light on the biological processes at play.
Historical and Cultural Perspectives
Historical accounts and anecdotes have played a significant role in perpetuating the myth of post-mortem hair growth. For instance, the opening of King Charles I’s sarcophagus reportedly revealed extraordinarily long hair, and there have been tales of hair growing out of coffins years after burial. “Philosophical Transactions and Collections” from 1700 reports “a woman buried at Nuremberg, whose grave being opened, forty-three years after her death, there was hair found issuing forth plentifully through the clefts of the coffin, insomuch that there was some reason to imagine the coffin had sometime been covered all over with hair.” Such stories capture the imagination and reinforce the medical mythology of hair growth after death, but they lack any scientific backing.
Biological Processes After Death
Upon death, the body undergoes significant changes. The cessation of the heart’s beating halts the oxygen supply to tissues, crucial for cell survival. Enzyme activity, essential for metabolic processes, diminishes as the body cools. Cells react to the lack of oxygen by ceasing to produce energy, eventually leading to cell death. This process is not immediate, but within a few hours, tissues begin to break down.
The hair follicle, one of the most metabolically active tissues in the human body, requires a substantial energy investment for hair fiber formation. The hair growth process is sustained by a rich blood vasculature around the hair follicles supplying nutrition, but this supply ceases after death. Consequently, the hair follicle, like other tissues, undergoes degenerative changes. Histological studies reveal that skin cells begin to degrade as early as 6 hours post-mortem, with specific changes observable in various skin layers and associated structures like sweat and sebaceous glands. By 18 hours post-mortem changes to the hair follicles can be seen as separating of the hair root cell layers and disintegrating dermal papilla cells.
Skin and Hair Changes after Death
Post-mortem, the human body undergoes a process called autolysis, where enzymes start breaking down the body tissues. The skin, being the largest and most exposed organ, shows significant changes. Histological studies indicate that skin cells begin to degenerate within hours after death. The retraction and dehydration of the skin, particularly around hair and nails, create the illusion of growth. The apparent increase in hair and nail length after death is a result of the surrounding skin drying out and retracting. As the skin dries and contracts, it pulls away from the hair and nails, making them appear longer. This phenomenon is often mistaken for actual growth. However, it is important to note that hair and nail growth requires active cellular division and energy supply, processes that are not possible after death.
There may also be an additional activity that could make it look as though hair is growing. During life, hair follicles cycle through an anagen growth phase, a regression phase called catagen, and then a telogen resting phase. The follicle then enters a new hair growth phase and starts making a new hair fiber. The old hair fiber is shed from the hair canal through an active process called exogen. While the old hair fiber is not actually growing, it is pushed up and out of the hair canal so it looks as though it is growing up until the time point it is shed. Whether a similar process might occur after death has not been looked at, but this process does occur in hair follicles in culture that are degenerating so it may be possible in the right environment.
Debunking the Myth: Scientific Evidence
The myth of post-mortem hair growth, while rooted in observable phenomena, lacks a biological basis. Hair and nail growth is a complex process, regulated by hormones and requiring an ongoing supply of glucose and oxygen, both of which are unavailable after death. The cells in the hair matrix at the base of the follicle divide rapidly during life, contributing to hair lengthening, but this process ceases soon after the heart stops pumping blood.
Similarly, nail growth depends on the production of new cells in the germinal matrix beneath the nail base. This process also stops after death due to the cessation of glucose supply. The illusion of nail growth post-mortem is, like that of hair, a result of skin retraction.
Implications in Forensic Science
Understanding the post-mortem changes in hair and nails is important in forensic science and medical research. It helps in estimating the time of death and understanding the conditions of a body at a particular post-mortem interval. For instance, the rate of skin retraction and dehydration can provide clues about the environmental conditions surrounding the body after death.
Research in forensic science has further explored the changes in hair after death, particularly focusing on post-mortem root banding (PMRB) of plucked hair fibers. PMRB is observed as an opaque band near the hair root in hair from decomposing bodies. It is a recognized phenomenon in forensic investigations and while it is not fully understood, some forensic scientists believe that it could aid in estimating the time duration since death. Advanced methods such as nano-flow liquid chromatography tandem-mass spectrometry (nLC-MS/MS) have been used to compare protein profiles in banded and non-banded hair sections, revealing compromised protein integrity in PMRB. It seems that as the proteins break down in the roots of the hair fibers, the breakdown is not evenly distributed and this results in the PMRB features. These findings highlight the need for further research to understand the physical and biochemical aspects of hair decomposition, which could improve forensic analysis accuracy and contribute to the broader field of forensic taphonomy (taphonomy is the study of how organisms decay and the word literally means “burial studies”).
The persistent myth of hair growing after death serves as a reminder of how folklore can often overshadow scientific facts. While the illusion of post-mortem hair growth is rooted in observable changes to the skin, it is crucial to understand that these changes are not indicative of life processes continuing after death. The retraction of skin and the robust nature of hair and nails contribute to the appearance of growth, but in reality, they are just manifestations of the body’s post-mortem changes. This understanding dispels the myths and highlights the fascinating interplay of biological processes that occur at the end of life.