A greenstick fracture is most commonly seen in which type of bone?

A greenstick fracture is a type of incomplete fracture typically seen in young, pliable bones. This type of fracture is characterized by the bone bending and cracking on one side while remaining intact on the other, much like a green twig. Greenstick fractures are most commonly associated with convex bone surfaces, as these surfaces are under tension during bending, leading to the fracture pattern described.

In children, whose bones have not fully ossified and have a higher mineral content than adult bones, the flexibility allows for this kind of fracture to occur more readily when subjected to a bending force. The other types of bones mentioned, such as completely ossified bones, concave bone surfaces, and flat bones, are less likely to experience greenstick fractures due to their different structural properties and the nature of forces they typically withstand. Therefore, the correct choice highlights the typical characteristics and occurrence of greenstick fractures in relation to bone surfaces.