This one made me wince, as I do have a child in the 3-6 age range.
As anyone who have, or are around small children, know, they are prone to running around and falling.
This is the case for a 4-year old girl who happened to fall onto an upright crochet hook. It punctured her upper left chest.. The child that proceeded to remove it herself. According to the case reports that I found, she was only taken to the hospital because of her annoying crying. After the initial examination, the little girl was taken to emergency surgery for a emergency median sternotomy.
She went on to stay at the hospital for another 5 days before she was cleared to go home.