how many deltas can a loop have
Statistics today show that sixty to sixty five of the population has loops on their fingers, thirty to thirty five percent have whorls as their fingerprint pattern and five percent have arches. A loop must have one or more ridges entering from one side of the fingerprint, and exit from the same side. Ulnar loops are loops that open toward the little finger and radial loops are just the opposite. Radial loops are loops that open toward the thumb. The most common pattern is the ulnar loop. Whorls are divided into four distinct groups: plain, central pocket loop, double loop and accidental. Whorls must contain a minimum of two deltas and must have a type line (pattern area of the loop surrounded by two diverging ridges). Arches are classified in two different groups; plain arches and tented arches. The ridges tend to rise in the center of the pattern. Tented arches have a sharp spike at the center.