![]() O If you cross a bifurcation, count each of its arms. O Fragments and dots are counted as ridges only if they appear as thick as the surrounding ridges. O The delta and core are not included in the ridge count. O As long as you touch or cross a ridge, you have a ridge count. LOOP PATTERNS: (1) one or more ridges enter upon either side, (2) recurve, (3) touch or pass an imaginary line between delta and core, and (4) pass out or tend to pass out upon the same side the ridges entered.īasic Requirements of a Loop: (1) Sufficient recurve, (2) Delta, and (3) Ridge count across a looping ridge Tented arches are indicated by: (1) Capital “T” in fingers number 2 and 7, and (2) Small “t” in fingers other than 2 and 7. Note: These three loop characteristics are, to repeat: (a) A sufficient recurve. Loop Type (Lacking One Characteristic): (1) one which approaches the loop, (2) may have any combination of two of the three basic loop characteristics, (3) lacking the third. It must be an angle of forty-five degrees or more from base ridge and (3) an upthrust must be as high as the surrounding ridges are thick. Upthrust Type Tented Arch: (1) an upthrust must be an ending ridge – a ridge which ends in space (2) an upthrust must make a definite change of direction from the basic ridge. Īngular Type Tented Arch: (1) formed by two ridges meeting at an angle (2) one continuous ridge cannot form an angle and (3) angle must be 90 degrees or less. Tented Arch: possesses an (1) angle, (2) an upthrust, or (3) two of the three basic characteristics of the loop. Indicated by: (1) Capital “A” in fingers number 2 and 7 (2) Small “a” in fingers other than 2 and 7. No (1) looping ridge, (2) an upthrust ridge, (3) an angle, or (4) a recurve. Plain Arch: (1) ridges enter upon one side, (2) make a rise or wave in the center, (3) and flow or tend to flow out upon the opposite side. Ridges are formed and become unique and permanent during approximately the fourth month of fetal life. Identical twins may have similar friction skin patterns but their individual ridge formations will not be the same. Thus, no two areas of friction skin will ever be the same. Environmental influences: pressures, stresses, and other physical factors such as disease and nutrition. Biological variations are due to environmental influences occurring during fetal development. Friction ridges are randomly formed because of biological variation. General patterns on the volar areas are determined by heredity and genetic master plan. Epidermis: (1) generating layer – innermost layer creates new cells, and (2) outer layer - mostly dead cells. Friction skin 2 main layers: (1) epidermis – outer layer, and (2) dermis - the inner layer. Friction skin: (1) ridges - elevated areas, and (2) furrows - depressionsģ. Undersides of fingers, palms, toes, & soles – corrugated skin structure: volar skin – biologist, friction skin – fingerprint examiner, and fingerprints – publicĢ. Tenets of Friction Skin Identification: (1) Unique & (2) Permanentġ. SWGFAST, Glossary - Consolidated 09-09-03 ver. ![]() Scientific Basis of Friction Skin Identificationįingerprint is an impression of the friction ridge of all or any part of the finger. Retrieved May 5, 2012, from Latent Print Examination: Fingerprints, Palmprints and Footprints: Bertillon System: (1) photograph, (2) portrait parle, (3) anthropometry proven inaccurate in Will and William West Case Visual memories (camera eyes) to identify previously arrested offenders by sight Ħ. ![]() Tattooing to identify and prevent desertion of mercenary soldiers Ĥ. Branding and even maiming were used to mark the criminal ģ. ![]()
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