A
fingerprint in its narrow sense is an impression left by the
friction ridges of a human
finger. The recovery of fingerprints from a crime scene is an important method of
forensic science. Fingerprints are easily deposited on suitable surfaces (such as glass or metal or polished stone) by the natural secretions of sweat from the
eccrine glands that are present in epidermal ridges. These are sometimes referred to as "Chanced Impressions".