Island A line that stands alone. An island does not touch another line and is totally contained in the pattern area of interest. Loop A curved line that begins and ends on the same axis. Rod A straight line that is generally found in the center of the fingerprint pattern area. Spiral A line that spirals out from the center of the fingerprint.
Spirals are common to whorl patterns.
A sweat-producing gland in the fingertip. Every finger contains many sweat glands. The moisture that they produce allows fingerprints to be electronically imaged. An arch that quickly rises and falls at a steep angle. Minutiae Points Line types contain common micro-features called minutiae.