Avulsion fracture by the extensor digitorum brevis muscle.

@article{Morse1989AvulsionFB,
  title={Avulsion fracture by the extensor digitorum brevis muscle.},
  author={H H Morse and Lynn Lambert and Danko Basch and Marty Lederman},
  journal={Journal of the American Podiatric Medical Association},
  year={1989},
  volume={79 10},
  pages={514-6}
}