Openings in the nose that allow the passage of air into the pharynx. The paired anterior openings are the anterior nares, or nostrils; the paired posterior openings at the back of the nasal cavity leading to the nasopharynx are the posterior nares.
Openings of the nose. The two external (or anterior) nares are the nostrils, leading from the nasal cavity to the outside. The two internal (or posterior) nares (choanae) are the openings leading from the nose into the pharynx.