The cavity of the nose (cavum nasi) occupies a central position in the facial skull. The bony septum nasi osseum, consisting of a perpendicular plate of the latticed bone and the opener connected at the bottom with the nasal crest, divides the bony cavity of the nose into two halves. In front there is a pear-shaped aperture (apertura piriformis), bounded by the nasal incisions (right and left) of the maxillary bones and the lower margins of the nasal bones. In the lower part of the pear-shaped aperture the anterior nasal spine (spina nasalis anterior) protrudes forward. Through the back holes of the nasal cavity, or choanae (choanae), the nasal cavity communicates with the pharyngeal cavity. Each choana is bounded from the lateral side by the medial plate of the pterygoid process, with the medial plow, the upper body of the sphenoid bone, from below by the horizontal plate of the palatine bone. The nasal cavity is divided into three walls: the upper, lower and lateral.
The upper wall is formed by the nasal bones, the nose part of the frontal bone, the latticed plate of the latticed bone and the lower surface of the body of the sphenoid bone.
The lower wall consists of palatine processes of the maxillary bones and horizontal plates of the palatine bones. On the median line of this wall, these bones form a nasal crest to which a bone septum of the nose joins, which is the medial wall for the right and left halves of the nasal cavity.
The lateral wall is formed by the nasal surface of the body and the frontal process of the upper jaw, the nasal bone, the lacrimal bone, the latticed maze of the latticed bone, the perpendicular lamina of the palatine bone, the medial plate of the pterygoid process of the sphenoid bone (in the posterior part).
On the lateral wall of the nasal cavity, three nasal conchaes are located one above the other. The upper and middle shells are parts of the latticed labyrinth, and the inferior nasal concha is an independent bone. Nasal shells divide the lateral part of the nasal cavity into three nasal passages: upper, middle and lower.
The upper nasal passage (meatus nasi superior) is bounded from above and medially by the superior nasal shell, and from below by the middle nasal shell. This nasal passage is located in the back of the nasal cavity. The posterior cells of the latticed bone open into it. Above the posterior part of the superior nasal cavity there is a wedge-latticed recessus (recessus sphenoethmoidalis), into which the aperture of the sphenoid sinus opens. Through this aperture, the sinus communicates with the nasal cavity.
The middle nasal passage (meatus nasi medius) is located between the middle and lower nasal shells. It opens the front and middle cells of the latticed bone, the aperture of the frontal sinus by means of a lattice funnel and a semilunar cleft leading to the maxillary sinus. The wedge-palatal opening (foramen sphenopalatinum) located behind the middle nasal concha connects the middle nasal passage with the pterygoid palatine fossa.
The lower nasal passage (meatus nasi inferior) is restricted from above by the inferior nasal shell, and from below by the nasal surfaces of the palatine process of the maxilla and the horizontal plate of the palatine bone. In the anterior part of the lower nasal passage, a nasolacrimal canal (canalis nasolacrimal) opens in the orbit.
Narrow sagittally located slit, limited by a septum of the nasal cavity from the medial side and nasal concha, is a common nasal passage.