ethmoïdales

Ethmoidal refers to structures related to the ethmoid bone. The ethmoid bone is a complex, unpaired bone located in the skull, forming part of the orbits and the nasal cavity. It is situated between the eyes and behind the nose, contributing to the anterior cranial fossa.

The ethmoid bone is characterized by its porous, sieve-like structure, which gives it its name, derived from the Greek word "ethmos" meaning sieve. It contains the cribriform plate, a perforated horizontal plate that separates the cranial cavity from the nasal cavity and allows olfactory nerve fibers to pass through, enabling the sense of smell.

Within the ethmoid bone are the ethmoidal sinuses, also known as ethmoid air cells. These are small, numerous cavities located within the ethmoid bone. They are divided into anterior, middle, and posterior groups. Inflammation of these sinuses is called ethmoiditis, a common form of sinusitis.

The ethmoidal arteries and veins supply and drain blood to and from the ethmoid bone and surrounding structures. The ethmoidal labyrinth refers to the lateral masses of the ethmoid bone, which contain the ethmoidal air cells and contribute to the formation of the lateral walls of the nasal cavity. The ethmoidal notch is a superior indentation that, when articulated with the frontal bone, forms part of the anterior cranial fossa.