While some sources list eight fingerprint patterns, the most commonly cited number of basic fingerprint patterns is seven. These patterns are categorized based on the ridge flow and formations on the fingertip. Keep in mind that variations within these categories exist.
The seven basic fingerprint patterns, as commonly understood, are derived from the broader classification schemes which sometimes include additional sub-categories or variations. These seven commonly mentioned are typically grouped as follows:
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Arches: These patterns are characterized by ridges that enter from one side of the finger, rise in the center, and exit on the other side. Arches make up a relatively small percentage of fingerprint patterns. Two main types exist:
- Plain Arch: A simple upward curve of ridges.
- Tented Arch: Similar to a plain arch, but with a sharper, more pointed peak in the center. The ridges may converge to form a small angle.
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Loops: These are the most common type of fingerprint pattern. Loops have ridges that enter and exit on the same side of the finger, curving around a central point. There are two main types:
- Radial Loop: The loop opens towards the radius bone (thumb side).
- Ulnar Loop: The loop opens towards the ulna bone (pinky finger side). This is the more common type of loop.
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Whorls: These patterns are circular or spiral in shape and contain two or more deltas (triangular areas where ridge patterns diverge). Several subtypes exist, often included in the broader eight pattern classification. One type is:
- Plain Whorl: A simple circular pattern.
The FBI recognizes eight patterns which includes variations within these categories (e.g., Central Pocket Loop, Double Loop, and Accidental whorls). The number of patterns recognized can vary depending on the classification system used. However, the aforementioned seven patterns cover the fundamental ridge flow characteristics.
The percentages of each pattern in the general population vary, but loops consistently represent the majority, followed by whorls, with arches being the least common.
