What cavities are contained within the lateral masses of the ethmoid bone?

The lateral masses of the ethmoid bone contain the ethmoidal sinuses, also known as ethmoid air cells. These sinuses are a collection of small, air-filled spaces located within the ethmoid bone, which is situated between the nasal cavity and the orbits of the eyes.

The ethmoidal sinuses play a significant role in the respiratory system by contributing to the warming and humidification of inhaled air, as well as reducing the weight of the skull. The anatomical position of these sinuses within the lateral masses of the ethmoid bone allows them to communicate with the nasal cavity, which is crucial for proper sinus drainage and function.

In contrast, the other options refer to different paranasal sinuses located in other parts of the skull. The sphenoidal sinuses are located within the sphenoid bone, the maxillary sinuses are found in the maxilla, and the frontal sinuses are located in the frontal bone above the eyes. Each of these sinuses has distinct anatomical features and functions, but they do not exist within the lateral masses of the ethmoid bone.