The nasal cavities are two irregular spaces, situated one on either side of the middle line of the face, extending from the base of the cranium to the roof of the mouth, and separated from each other by a thin vertical septum. They open on the face through the pear-shaped anterior nasal aperture, and their posterior openings or choanae communicate with the nasal part of the pharynx. They are much narrower above than below, and in the middle than at their anterior or posterior openings: their depth, which is considerable, is greatest in the middle. They communicate with the frontal, ethmoidal, sphenoidal, and maxillary sinuses. Each cavity has a roof, a floor, a medial and a lateral wall. The roof is formed in front by the nasal bone and the spine of the frontal, in the middle, by the cribriform plate of the ethmoid, and behind by the body of the sphenoid, vomer and palatine bones. The floor is formed by the palatine process of the maxilla and the horizontal part of the palatine bone. The medial wall is formed, in front, by the crest of the nasal bones and frontal spine, in the middle, by the perpendicular plate of the ethmoid, and behind, by the vomer and the rostrum of the sphenoid, and below by the crest of the maxillae and palatine bones. It presents, in front, a large, triangular notch, which receives the cartilage of the septum. The lateral wall is formed, in front, by the frontal process of the maxilla and by the lacrimal bone; in the middle, by the ethmoid, maxilla, and inferior nasal concha; behind, by the vertical plate of the palatine bone, and the medial pterygoid plate of the sphenoid. On this wall are three irregular anteroposterior passages, termed the superior, middle, and inferior meatuses of the nose.

Cavitas nasi

Cavité nasale