Friction ridge skin is more commonly known as fingerprints. Friction ridge skin is the skin that is on the palms and fingers of the hand and soles and toes of the feet. Friction ridge skin has raised ridges and furrows between them; this corrugated surface is designed for grasping and holding items. At the tops of the ridges there are sweat pores. The ridges do not simply start on one side of the finger and travel straight and uninterruptedly to the other side of the finger but rather these ridges stop, start, and branch into multiple ridges to form unique and individual patterns. Friction ridge skin forms in the 12th to 16th week of fetal development, and except for changing in size due to growth, remains the same throughout a persons life until decomposition.