Basically, we refer to fractures not only based on the name of the bone broken but also on the characteristics of the break itself. Closed fractures are those in which the skin is not broken. The bone is fractured, but the overlying skin is intact. Compound fractures are breaks in which the broken bone protrudes through the skin, and is exposed to the outside. Compound fractures are risky in that the bones can be contaminated with dirt resulting in an infection.
Bones grow from the ends.
In animals less than one year of age, there are soft areas near the ends of each long bone where growth takes place. These soft areas are referred to as growth plates or epiphyseal plates. Because these are areas of growth, they are rich in immature non-calcified cells that form a soft, spongy area of the bone. These growth plates are more easily fractured because they are the weakest part of the bone. The distal ends of the femur and humerus seem to be particularly susceptible to this fracture.