The nose is the most prominent place on the front of the skull. Its structure is very complex, but in a simplified way it can be divided into 3 components: the external, nasal cavity and sinuses. The beginning of the upper respiratory tract is the nasal cavity. It is located in the central part of the facial skull. This is, in fact, an air channel through which there is communication with the outside world (through the nostrils), and on the other hand - with the nasopharynx.
The nasal cavity opens with a pear-shaped opening (aperture), behind which there are paired internal openings of the nose (choanae). This is, so to speak, the back nostrils. They connect the nasal cavity with the nasopharynx. The entire cavity is divided sagittally by a septum into right and left halves. In most cases, they are asymmetrical, so a person often has a natural curvature of the nasal septum. An interesting fact is that up to 5 years the septum is even, and then its intensive growth begins. Cartilage outstrips bone growth and a curvature is formed. It occurs in 95% of men.
The size of the nasal cavity grows with age. For example, in an adult it is 3 times more than in a child up to a year. The cavity is bounded by five walls: superior, inferior, posterior, lateral and medial. It starts with a prelude. There is no mucous membrane here, there is skin with numerous hairs necessary for cleansing and warming the inhaled air. In children, the internal structure as a whole is similar to an adult, but at the same time, the departments are undeveloped and compacted. For this reason, complications in the form of rhinitis are so common in children.
Functions of the nose
The main functions include the following:
- The incoming air is warmed and stored here.
- Providing oxygen to tissues.
- When inhaled, the incoming air is moistened and cleaned of dust, disinfected, humidified.
- The entire nasal cavity, its sinuses and pharynx act as resonators, thanks to which the voice acquires an individual color and tonality (timbre). For the same reason, with diseases in the nasal cavity, swelling occurs and the timbre of the voice changes.
- Olfactory function - in the mucous membrane there are receptors of the organ of smell. This function is very important in a number of professions: perfumery, chemistry, food.
Smells are also important in the production of saliva for food.
Nasal passages: introduction
Nature provides for the supply of warm and clean air to the tissues of the lungs, which are particularly delicate. When inhaled through the mouth, this does not happen, and the nasal cavity performs these functions. Namely, this is what the nasal passages do. It should be noted that the bones of the nasal cavity andspaces are paired.
What is this?
These are three "protrusions" located one above the other, on the lateral wall of the lateral nasal cavity. In anatomy they are called "shells". The largest nasal concha is the inferior one. This is a separate bone, and the lower shell is considered true. And the middle and upper shells are components of the labyrinth of the ethmoid bone. With these shells, the nose in its lateral section is divided into three narrow longitudinal slits - the passages of the nasal cavity.
Air currents pass through these passages. Accordingly, there is an upper, middle nasal passage and lower (meatuses). Each of them is formed by walls: the upper, inner, lateral outer, and the lower, formed by the maxillary bones.
The upper two passages lead to the sinuses, the lower one communicates with the eye socket. The middle nasal passage leads to the maxillary sinuses. The passages at the nose are narrow, the mucous membrane is richly supplied with blood vessels. All this together provokes a very rapid development of edema during hypothermia, pathogens, or during an allergic reaction.
There is also a space between the medial wall (nasal septum) and the posterior sections of the nasal concha, which is called the common nasal passage - meatus communis.
Upper nasal meatus
Occupies a space between the middle and upper shells, is the shortest. Therefore, it is, as it were, retracted into the far part of the nasal cavity. It has openings into the posterior ethmoid cells. It opens the mainnasal sinus, which is called the sphenoid sinus.
As an anatomical structure, the upper passage is the olfactory zone, the olfactory nerve passes here. Its function is to distinguish odors.
In the upper nasal passage, from the anterior cranial fossa through the lattice of the ethmoid bone, in addition to the olfactory nerve, there are also nasal veins. Branches of the maxillary artery, which is the main artery supplying the nose and postganglionic fibers, pass from the pterygopalatine node to innervate the glands of the nasal mucosa through the pterygopalatine foramen with the fossa of the same name in the indicated nasal passage.
Middle meatus
Located between the middle and inferior turbinates of the ethmoid bone. It is longer and wider. The middle nasal passage is divided into basal and sagittal parts. All sinuses open here (frontal and maxillary - maxillary sinuses), except for the main, middle and anterior cells of the ethmoid bone. The main function is the direction of air flow.
The middle nasal passage is nevertheless of more important clinical significance due to communication with the frontal and maxillary caves. From here originate inflammation of the sinuses - sinusitis, ethmoiditis. Behind the middle nasal choana there is a sphenopalatine opening, through which the pterygopalatine fossa and the middle nasal passage communicate. Through it, the sphenopalatine artery and the nerves of the pterygopalatine node, its nasal branches, pass into the nasal cavity.
Inferior meatus
Found above solidthe palate (bottom of the mouth) and the lower nasal concha from above. The outer wall of this passage is the lower part of the wall of the maxillary cave. The nasolacrimal canal with the duct of the same name opens into the anterior part of the lower nasal passage. It begins in the eye socket, which therefore also communicates with the lower nasal passage. This move is the widest and longest. The sinuses do not open into it.
In clinical ENT practice, the significance of this nasal passage is that the maxillary sinus is punctured through it in the treatment of purulent sinusitis, as well as for the purpose of diagnosis.
