explain these surprisingly(?)different findings xrays showed that the 75 year had fracture ribs but not the 9y

Question

A 75year old woman and her 9year old granddaughter were in atrain crash in which both sustained trauma to the chest while seated next to each other.

Answer 1

The ribs of children are mostly cartilage (flexible) and fractures to them are exceptionally rare, even with significant trauma. As we age, the ribs become ossified (more bony) and then more brittle in the later years.

Also, in sudden stop types of injury, a more massive person sustains more trauma (force=mass x velocity). So the fact that she was bigger is also important.

Answer 2

The 75 year old is OLD. She has osteoporotic bones that are easily fractured. Also, her thorax is much more rigid (less flexible) than the nine year old's. Consequently, she is much more likely to have fractures after significant chest trauma.

Answer 3

Osteoporosis & old age for granma.
youth and still growing bones may still be soft and some what flexiable.
Granma has a larger diameter chest to take the brunt of the blow.

Answer 4

The older lady's bones were probably a little bit more fragile. That is a common problem with the elderly.