The assessment of post mortem structural changes in the human epidermis.

Area of Science:

• Forensic pathology
• Dermatology
• Cell biology

Background:

• Understanding post mortem changes in human skin is crucial for forensic investigations.
• Keratinocyte morphology undergoes distinct alterations after death, influenced by environmental factors like refrigeration.

Purpose of the Study:

• To characterize epidermal and keratinocyte changes in refrigerated human skin specimens post mortem.
• To establish the potential of these changes for estimating post mortem intervals (PMI).
• To differentiate between ante mortem and post mortem skin samples.

Main Methods:

• Analysis of intact skin specimens from human corpses stored under refrigeration.
• Microscopic examination of epidermal layers, focusing on keratinocyte structure and nuclear morphology.
• Quantification of specific cellular alterations over time (first 8 days post mortem).
• Development of regression equations for post mortem time estimation.

Main Results:

• Spinous layer keratinocytes exhibit crescent-shaped nuclei with surrounding clear zones, increasing daily post mortem.
• Basal layer keratinocytes show distortion, ballooning, and pyknotic nuclei, leading to epidermal-dermal separation.
• A statistically significant correlation was found between the frequency of spinous layer changes and post mortem time, allowing estimation within one day accuracy.
• The combined presence of both spinous and basal layer changes aids in distinguishing post mortem samples.

Conclusions:

• Specific keratinocyte alterations in refrigerated human skin are reliable indicators of post mortem changes.
• The quantitative analysis of these changes enables accurate post mortem interval estimation.
• These findings contribute to forensic science by providing objective criteria for assessing skin samples.