Persistency of Friction Skin Histology research has provided us with knowledge of skin cell regeneration and growth. The deepest layer of epidermal cells (Stratum Basale) receive nourishment and oxygen from the capillaries in the dermis. This makes it possible for these cells to reproduce and grow. These cells are constantly reproducing and therefore new cells push the older cells further and further away from their source of nourishment and closer to the skin surface. As they migrate to the skin surface they are constantly changing - the result of a process called keratinization. They fill up with the protein keratin - a material that limits water loss from the body. When they eventually reach the skin surface - after approximately 30 days - they are flattened dead skin cells that are 'sloughed off'. Friction skin persistency is attained as a result of this constant cycle of cell reproduction, growth and migration. |
Friction Skin Growth |
Major Ridge Path Configuration Major ridge path formations are sometimes referred to as 1) Ridge endings (ridges that end abruptly) 2) Bifurcations (ridges that appear to split apart and continue on as two ridges) 3) Enclosures (ridges that appear to split in two and then rejoin) 4) Short ridges (consist of at least two ridge units) and 5) Ridge dots (only one ridge unit). Others have been known to disagree with this and have stated that only two major ridge path formations actually extist - ridge 'endings' and 'bifurcations'. Everything else is just a derivative of these. As David Ashbaugh explains in his book entitled "Quantitative-Qualitative Friction Ridge Analysis"..."A major ridge path deviation does not develop in isolation. Other ridge formations must develop around it and in concert with it. Therefore all major ridge path deviations display interaction with surrounding ridges." (An extremely important point for the Friction Ridge Identification Specialist to remember when analyzing friction ridge prints.) |
