Previous investigations on calvarial fractures in infants have shown that the flexibility and displacement of the infant calvarial are not sufficient to avoid fractures as a result of fall. From a table height onto hard ground - and in special cases, fractures cannot be avoided even after falls onto softly cushioned ground. The skull fractures are located in paper-thin, transparent, single-layer bone areas without diploe. The results of previous literature were compared with investigations of the skulls of 82 infants (from neonates up to infants 14 months of age). Congenital fissures, cranioschisis, locally retarded ossification in the cranium and craniotabes are all weak points where fracture has a tendency to occur even if the impact is minor. These ossification defects are increased in the ossa parietalia, but can also be found in the os frontale or in the os occipitale. The location is not always the same but can be detected by locating the skull transparency using diaphanoscopy.