The pattern of this fracture is characterized by an incomplete metaphyseal fracture which is angulated (varus/valgus; flexion/extension). At least one cortex is intact and there is no rotation. Any varus/valgus gap should not be more than 2 mm in an AP view.
To avoid an incorrect classification in children below 5-6 years of age, the position of the capitellum needs to be identified. In this age group, the real size of the capitellum in the lateral view is determined by placing a circle with a diameter equal to that of the humeral shaft concentrically over the visible ossific nucleus. The fracture is classified as a 13-M/3.1 II fracture if the Roger's line (red line) does not intersect the circle.
Note: Be aware of the possibility of nonaccidental injuries in younger children.