Less than 2 = 3 feet
Greater than 2 = 5 feet
Consider head CT in children with head injury after this mechanism of injury. For further details regarding Kuppermann's head CT decision rule for children with head trauma, click here.
Source
Kuppermann N et al. Identification of children at very low risk of clinically-important brain injuries after head trauma: A prospective cohort study. Lancet 2009 Sep 15