Enamel in longitudinal section of tooth - human, adult. Thin ground section.

At the left side surface of enamel in cuspal region; the parallel horizontal arrangement of stacks of rods (prisms) is evident. At the right side area of dentin (dark area). Incremental lines (striae) of Retzius run as curved lines (from bottom to middle top) and presented successive apposition of layers of enamel. Hunter-Schreger bands (lines) cross diagonally from the top right side towards the middle half of the enamel. These light and dark strips originate at the dentinoenamel junction and are the result of the change in direction of enamel prisms as well as a different content in organic material in light/dark zones.