A thorough knowledge of normal radiological anatomy is necessary for detection and evaluation of pathological changes. In pediatric radiology, normal anatomy and normal proportions of anatomical structures may differ considerably from the adult, and may vary during growth. Therefore, in pediatric radiology there is a multitude of measurements, that in the individual patient is important, but that for the radiologist is not meaningful or even possible to keep in mind. This holds true both for the experienced pediatric radiologist, and for those who practise pediatric radiology only occasionally. This volume is written for both categories. In the literature, normal values are calculated and presented in many different ways, that are not always easy to compare, or easy to use in daily work. Therefore, we have revised and recalculated the data given by authors, in order to present the statistical upper and lower normal limits as between plus and minus two standard deviations (± 2SD). This means that about 2% of a normal population will be assessed as abnormally large and around 2% abnormally small with respect to the parameter assessed. In this way, the presentation throughout the book is uniform, and hopefully easy to use. All figures have been redrawn and computed in an attempt to make them as clear as possible.