Abstract
1. A defect of the middle of one tibial crest is described in young healthy ballet dancers.
2. The clinical and radiological characteristics have been studied in four cases, and the histological appearances in two.
3. The defect is concluded to be an incomplete fatigue fractureâa fatigue infraction.
4. A fifth, uncertain, case has been added tentatively, as presenting a possible serious complication, namely acute fracture from muscle action.
5. The diagnosis, treatment and prognosis are mentioned, with emphasis on the importance of adequate clinical and radiological examination in cases of obscure mid-tibial pain, tenderness or swelling.