Chest wall bruising from 5-point car seat harness as a mimicker of child abuse.

Bruising rarely presents in infants younger than 9 months who are not ambulatory and is more prevalent among children beginning to walk, or "cruisers." We present the case of a healthy 3-month-old infant with asymptomatic, symmetric, bilateral, large bruises on the bony chest sparing the mid-chest/sternum with a negative non-accidental trauma work-up. The noted pattern of bruises matched the bilateral shoulder straps of a 5-point harness of the car seat belt designed for infants.