[Pathogenesis of fibrous cortical defect and non-ossifying bone fibroma].

We were able to show in eighty-one cases that fibrous cortical defects or non-ossifying fibromas of the bone occur only in areas, where tendons insert into the perichondrium of the epiphyseal plate. During growth these tumor like lesions move towards the diaphysis following a cortical line, which begins at the point of insertion of the tendon and is parallel to the longitudinal axis of the bone.