[The "crescent sign" in older children (author's transl)].

The "crescent sign", a dense, convex line parallel to the surface of the kidney, has only been reported in small children with obstructive uropathy during urograms. Two patients (aged 13 and 14 years) with this sign are described. The cause of this appearance is discussed and related to the striations seen on late films in adults with urinary obstruction.