Fingerprint patterns: • Arch: Ridges flow one above the other in a gently arching configuration. There are no deltas or recurves. • Tented arch: Arch pattern with at least one up-thrusting ridge at right angles to the ridges above it. • Ulnar/radial loop: Consists of at least one free recurving ridge and one delta. These patterns are named after the ulna and radius, the bones of the forearm. In ulnar loop, recurves originate from and return to the little finger side of the hand, whereas recurves in radial loops originate from and return to the thumb side of the hand. • Whorl: Consists of at least one recurving ridge and two deltas. A straight line drawn between the points of delta will cross at least one of the ridges revolving around the core. • Central pocket loop: Similar to the whorl, except that none of the recurving ridges will be crossed by a straight line between the points of delta. • Double loop: Consists of two looping formations and two deltas. • Composite: Contains at least two of the previous described basic patterns, excluding the arch. • Accidental: Contains two deltas, one in front of an up-thrusting formation and the other in front of a recurving formation.
