Fig. 8.

Calculation of intercellular forces. A: an individual cell generates traction forces but not tugging forces. B: for pairs of cells, there are tugging forces between them. C: the intercellular force experienced by a cell is equal to the vector sum of its tugging forces. D: for a monolayer of cells, each cell produces a tugging force on its neighbors, but these forces cannot be solved for uniquely. E: as before, the intercellular force on a cell is balanced by the vector sum of its tugging forces. F: intercellular forces for cells within a monolayer can be used to assess intercellular tension.