RIDGE CHARACTERISTICS MINUTIAE A CLOSER LOOK AT FINGERPRINTS

RIDGE CHARACTERISTICS (MINUTIAE): A CLOSER LOOK AT FINGERPRINTS

RIDGE CHARACTERISTICS A fingerprint is not determined by its general pattern but by a careful study of ridge characteristics Can be ridge endings, bifurcations, enclosures, and other ridge details, which must match in two fingerprints to establish their common origin If two prints are to match, they must have identical ridges in the same location In a court setting, a comparison must be shown by an expert to prove the identity of a

RIDGE CHARACTERISTIC COMPARISON

FACTS The average fingerprint has as many as 150 ridge characteristics Most prints recovered are crime scenes are partial, showing only a segment of an entire print The expert can then only compare a small number of minutiae Experts have debated that 8 -16 minutiae are necessary to identify two fingerprints as the same Final determination must be

Ridge Characteristics Use these characteristics as points of identification when comparing fingerprint samples. The more points you can find in common, the better the match!

MOST COMMON EXAMPLES Dot: An isolated ridge whose length approximates its width in size Ending ridge: A single friction ridge that terminates within the friction ridge structure Bifurcation: one friction ridge divides into two friction ridges Enclosure: a single ridge that bifurcates and rejoins to continue as a single ridge

EXAMPLES

LETS TAKE A LOOK…

Try It! 1 – Blow up your balloon just until it starts to expand twist the end to keep the air from coming out. Do not tie it off! 2 – Use an ink pad to make a print with your best fingerprint and label which finger it is with a permanent marker. Write your name on the balloon and also be sure to write down the pattern of the print. 3 – Blow up the balloon to full size and tie the end. 4 – Analyze the fingerprint to find ten ridge structures that we have discussed. Use a permanent marker to circle these structures and label them A through J. On a separate sheet of paper, identify which ridge structures A through J are. Also answer the following questions on the paper: Which ridge structures were most common in your fingerprint? Which ridge structures were most common in your group? Were there any structures that were not found in your print?