an event that occurs in a regular flow of papillary ridges

Friction ridge characteristics that are used to individualize a fingerprint. Minutiae occur at points where a single friction ridge deviates from an uninterrupted flow. Deviation may take the form of ending, division, or a more complicated “composite” type.

A minute particular; a small or minor detail; -- used chiefly in the plural.

a small or minor detail; "he had memorized the many minutiae of the legal code"