There is no definite theory yet for the mechanism by which the pattern of epidermal ridges on fingers,
palms and soles forming friction ridge skin (FRS) patterns is created. For a long time growth forces in
the embryonal epidermis have been believed to be involved in FRS formation. More recent evidence
suggests that Merkel cells play an important part in this process as well. Here we suggest a model for
the formation of FRS patterns that links Merkel cells to the epidermal stress distribution. The Merkel
cells are modeled as agents in an agent based model that move anisotropically where the anisotropy is
created by the epidermal stress tensor. As a result ridge patterns are created with pattern defects as
they occur in real FRS patterns. As a consequence we suggest why the topology of FRS patterns is indeed
unique as the arrangement of pattern defects is sensitive to the initial configuration of Merkel cells
