In osteomyelitis, bacteria gain access to the subperiosteal space in the metaphysis, which is considered the path of least resistance. What factor makes this route for bacteria the path of least resistance?

The factor is the porous nature of the cortex of the bone

Explanation:

The path of least resistance results form the subperiosteal space due to the porous or mazelike structure of the cortex of the bone as it's inflammatory response prevents further spread within the bone.