[The so-called chondrodystrophia of the newborn (author's transl)]

Chondrodystrophia (now: Achondroplasia) formerly believed to be a uniform disease rather is an entity comprising up till now at least ten radiologically differing types. Definite diagnosis of these types can only be made radiologically although certain clinical features are of additional help. For practical purpose a schematic representation of these types is given, based upon the classification of congenital osteochondrodysplasias by the ESPR (European Society of Pediatric Radiology, Rome, 1969). It emphasizes the characteristic radiological signs and describes the typical changes in body proportions. In a second part the single diseases are discussed according to the scheme with their radiological differential diagnosis and their prominent changes in the skeletal system. Some examples are given for possibly associated malformations and final prognosis.