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.

Our society is entering its fourth decade of existence, as of the 30th Annual Meeting in London, and we felt that this event merited reflection - a look back into the past - so as to better appreciate where we come from and where our sub speciality stands today, also in order to understand our colleagues from the different areas in Europe. It is our hope that paediatric radiology in Europe will thereby be strengthened now that old barriers have fallen. At the second conjoint meeting of the ESPR and the SPR in Stockholm in 1991 a group of senior pediatric radiologists from all parts of Europe who felt that this occasion should be marked took the initiative to produce a book on the history of paediatric radiology focussing on the develop ments leading to the creation of the ESPR. We thank all the colleagues who participated in the initial meeting to plan this book in Stockholm in 1991 and again at the Budapest Meeting in 1992 and who subsequently prepared contributions for it. These are the authors of the respective chapters and with them we hope that our readers will appreciate this effort. Unfortunately, we were not able to cover every European country, in spite of our attempt to do so."