Postmortem Microscopic Changes Observed at the Human Head Hair Proximal End

Abstract

Only two types of human hair roots (proximal ends) derived from decomposing scalps are reported in the literature. The most common representation of the putrid root includes a postmortem dark root band in published photomicrographs. In this study, 22 cases were reviewed in which there was reliable time of death documentation from medical investigator reports. A review of these cases finds that the most common putrid hair proximal end change does not contain the postmortem root band. Four primary types of hair proximal end postmortem change were identified. This study finds no correlation of time of death with scalp hair proximal end decomposition. In addition two examples are presented that suggest that hair roots do not decompose after fresh removal from the scalp and exposure to the outside elements.

A Review and Conceptual Model of Factors Correlated with Postmortem Root Band Formation

“…Overall, Domzalski's work showed that less keratinized layers of the hair root are more susceptible to degradation compared with fully keratinized layers (this finding was initially reported by Petraco et al ), and that humid and aqueous conditions exhibited strong positive correlations with hair root band formation. In agreement with the experiments described by Linch and Prahlow , ambient air alone does not lead to advanced decompositional changes in ex situ antemortem head hairs. Domzalski reported that antemortem root banding (AMRB) can be observed in ex situ head hair samples exposed to certain environments.…”

“…The frequency of hair sampling for microscopical analyses and the type of mounting medium used were not provided. No apparent changes were observed for any of the hairs examined . These results suggest that ambient conditions alone do not lead to advanced decompositional changes in ex situ antemortem head hairs.…”

“…According to Linch and Prahlow , this observation suggests that the sebaceous gland may be responsible for band formation at least in the hair shaft. This is in disagreement with the hypothesis made by Collins , Linch et al , and Hietpas et al . This again suggests that more than one mechanism exists for the formation of PMRBs, and which mechanism takes place or dominates may be determined by a given, specific set of conditions.…”

Evaluation of Histologic Changes of the Skin in Postmortem Period

“…Currently, there is very limited scientific information available regarding the process of sebaceous gland and hair follicle degeneration. 10 Further studies are required to evaluate these changes and characterize the postmortem changes. The study is limited by the small sample size and evaluation of skin changes in a common environmental setting.…”

Interpreting biological degradative processes acting on mammalian hair in the living and the dead: which ones are taphonomic?

“…The preferential invasion of anagen and catagen roots is attributed to these roots being softer and more easily degraded, unlike telogen roots that are bulbous and hardened through the keratinization process [34]. Although the precise mechanism responsible for PMB of hairs remains unknown, Linch & Prahlow [35] suggest that microbial and autolytic activities may be of importance.…”