Shaken baby syndrome: a flawed biomechanical analysis.

To the Editor, We are gravely concerned that the conclusions reached by Bandak [1] may be invalid due to apparent numerical errors in his estimation of forces experienced in an infant neck during vigorous shaking. More specifically, we have repeated the author’s calculations and we find values of neck forces that are actually more than 10 times lower than those presented in Bandak’s Table 3. Using the free body diagram of the infant head and neck (Fig. 3), Bandak identified the two components of neck force during rotation of the head—the tangential force F t and the normal force Fn. Bandak described the basic equations for neck forces during a simplified shaking event, but did not present detailed methods for calculating the upper neck loads. We define them here for completeness: