[Value and technique of measuring the tibia length in pathological conditions of the newborn (author's transl)].

Together with determining the bone age of the immature and/or small-for date neonate, it is possible to work out the length of the tibia on the profile X ray of the leg. Authors have drafted up a scale of growth, featuring the 10 th, 50 th and 90 th percentiles common for boys and girls ranging from 28 to 42 weeks of gestation and they propose this new criterion for the study of pathological neonates, particularly the small-for-date. The method has a second advantage: it is possible to follow the increment of the tibia length by X rays taken at regular intervals and thus to estimate the various factors that can interfere with the child's growth, and in the first place, the quality of the food given to the child.