The nasal passages are located in the center of the human face, projecting from the face, and are visible to the naked eye as bilateral nostrils, the wings and bridge of the nose, and the root of the nose. The anterior border of the nasal cavity is the anterior nostril and the posterior border ends at the posterior nostril, which communicates with the nasopharynx.
Each side of the nasal cavity is bounded by the nasal threshold and divided into the nasal vestibule and the intrinsic nasal cavity. The entire nasal cavity is a long, narrow cavity with a narrow top and wide bottom, resembling a conical structure. The bilateral nasal cavity is divided into left and right parts by the nasal septum.
The lateral walls of the nasal cavity are more structurally complex, with upper, middle, and lower turbinate attachments, as well as the natural openings of each group of sinuses.
The surface of the nasal vestibular region is covered with skin, and the surface of the intrinsic nasal cavity is covered with mucosal tissue. The nasal cavity serves a variety of functions including ventilation, filtration, moisturization, warming, and olfaction.