They are not a fall injury.

The mechanism is compression of the chest front to back — the rib is levered over the transverse process of the vertebra and breaks at the back.

In an infant, essentially the only thing that produces it is a pair of adult hands around the chest, squeezing.

Not shaking a rattle.

Not a car seat.

Not rolling off a sofa.

Not, and Dr.

Bright addressed this directly because somebody always raises it, ordinary CPR, which has been studied and which does not produce posterior rib fractures in infants in any meaningful number.