Ridges form perpendicular to lines of greatest stress. The mechanical instability theory regards ridge formation as a consequence of a buckling process. There are two main theories that aim to explain the processes underlying friction ridge formation. What are the theories of friction ridge development? By end of second trimester, sweat ducts and pores appear along epidermal ridges.Sweat glands and epidermal– dermal ridge system continue to mature and enlarge.Volar pad regression and friction ridge development continue by week 16 permanent minutiae are set.Basal layer becomes more prominent and forms folds of epidermis into dermis (primary ridges).Volar skin is layered epidermis on top of shapeless fibrous dermis.Volar pads less prominent then disappear friction ridge units develop.At 7–8 weeks volar pads begin to form from mesoderm.Limbs rapidly develop from about 4 weeks: arms, legs, knees, elbows, fingers, toes seen at about 8 weeks.Endoderm – forms other major organ systems including gastrointestinal tract, respiratory tract, urinary tract.Mesoderm – forms connective tissue of dermis.Ectoderm – forms the epidermis, including friction ridge skin.Gastrulation – early single ball of cells reorganises into three primary tissues.Fertilisation of egg initiates embryonal development.They undergo various phases, of which crucial events occur by the early weeks of the second trimester. The evaluation of fingerprint pattern may be useful to define risk groups.Fingerprints develop during early fetal life. Future research must define simple, low cost screening methods for preselection of subjects at higher cardiovascular risk or for exclusion of low risk subjects. The analysis of typica and other ridges characteristics requires a more elaborated system. The number of ridges per square mm was comparable in all pattern classes. The remaining classes were statistically less important. the main proportion of subjects with cardiovacular risk factors (91%) had arches (41.2%) and loops (either single, 38.2% or double 11.7% for a total of 49.9%). Subjects in classes 1, 2, 3 were included into the analysis made comparing FP patterns and ultrasound.įor each FP pattern: A. Four classes were defined: 1: normal intima-media (IMT) complex 2: IMT thickening 3: non-stenosing plaques (50%). Arteries were evaluated with high-resolution ultrasound at the bifurcations. Ultrasound evaluation of carotid/femoral arteries in asymptomatic subjects. Mixed figure: composed of different figures. Pocked loop: like the loop but with a small circle in the turning point. Double loop: like loops but with two loops inside: one standing, one hanging. Loop: lines coming from one site returning in the middle to the same site. Tentarch: like arches but with a rising stick in the middle. Arch: lines form waves from one site to the other side. This study compared FP patterns with cardiovascular risk factors: 7 main types of FP were used: 1. The point where a line stops or splits is defined typica' (their number/amount constitute identification patterns). Ridges are present on fingers/hands forming curved lines of different sizes/patterns. Fingerprints (FP), characteristic of humans, are impressions due to skin marks (ridges) on fingertips.
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