Final answer:
The ethmoid bone is located between the eyes and forms the medial wall of the eye sockets, part of the cranial floor, and most of the roof of the nasal cavity. It also includes the crista galli and cribriform plates.
Step-by-step explanation:
The ethmoid bone is the light and fragile bone located between the eyes, playing a significant role in the structure of the skull. It forms a part of the medial wall of the eye sockets, a small portion of the cranial floor, and most of the roof of the nasal cavity. The ethmoid bone contains several small, air-filled spaces known as the ethmoid air cells, which are part of the paranasal sinus system.
Within the cranial cavity, it also contributes to the floor of the anterior cranial fossa through a small area at the midline. This includes two vital structures: the crista galli, which is an upward projection, serving as an attachment point for the brain's covering layers, and the cribriform plates, featuring numerous openings called olfactory foramina for the passage of nerve branches from the nasal cavity to the brain.