What is the main role of the ethmoid bone?

The main role of the ethmoid bone is to support the nasal septum and the orbital cavity, which is why this choice is correct. The ethmoid bone is a complex structure located between the nasal cavity and the orbits of the eyes. It plays a crucial role in separating the nasal cavity from the brain and contributes to the formation of the nasal septum, which divides the nasal passages. Additionally, due to its position, it supports the orbits, the eye sockets, enhancing the structural integrity of these spaces that house the eyes.

The ethmoid bone’s unique arrangement of sinuses and the cribriform plate also play important roles in olfaction, as they provide a pathway for the olfactory nerve fibers. This gives it significance not just in structural support, but also in sensory function, particularly relating to the sense of smell.

The other options do not accurately represent the primary function of the ethmoid bone; for instance, it does not primarily serve to form the back of the skull, articulate with zygomatic bones, or provide structural rigidity to the forehead. These functions are associated with other bones in the skull and face.