In transverse fractures the elastic pull of the periosteum is an additional factor to muscle pull in producing angular and overriding deformity. It also tends to lock overriding fragments by its mechanical action under direct traction. It also by its elastic action tends to cause angular deformity, if reduction is not anatomically perfect. However, when anatomically perfect reduction is obtained, this elastic action of the periosteum tends to maintain it. Therefore, manipulation which will take advantage of these properties of the periosteum is advisable.