The nose is the most prominent place on the front of the skull. His structure is very complex, but simplified it can be divided into 3 components: the external, nasal cavity and sinuses. The beginning of the upper respiratory tract is the nasal cavity. Located in the central part of the facial skull. This is, in fact, the 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 is opened with a pear-shaped hole (aperture), behind which are located the paired inner holes of the nose (choana). These are, so to speak, the posterior nostrils. They connect the nasal cavity with the nasopharynx. The entire cavity is sagittally divided by the septum into the right and left halves. In most cases, they are asymmetric, so a person often has a natural curvature of the nasal septum. An interesting fact is that up to 5 years the septum is smooth, and then its intensive growth begins. Cartilage is ahead of bone growth and a curvature is formed. It is observed 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, 3 times. The cavity is limited by five walls: upper, lower, back, lateral and medial. It begins on the threshold. There is no mucous membrane, 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 the departments are undeveloped and compacted. For this reason, children often have complications in the form of rhinitis.
Nose function
The main functions include the following:
- The incoming air here is warmed and stored.
- Providing oxygen to tissues.
- When inhaled, the incoming air is moistened and cleaned of dust, disinfected, moistened.
- The entire nasal cavity, its sinuses and pharynx - play the role of resonators, thanks to them the voice acquires an individual coloring and tonality (timbre). For the same reason, with diseases in the nasal cavity, edema occurs and the timbre of the voice changes.
- Olfactory function - the receptors of the organ of smell are located in the mucosa. This function is very important in a number of professions: perfumery, chemistry, food.
Smells are important in the production of saliva for food.
Nasal passages: introduction
Nature provides for the entry of warmed and clean air into the lung tissue, which is distinguished by special tenderness. 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 is worth noting that the bones of the nasal cavity and space are paired.
What it is?
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 lower 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 slots - the passages of the nasal cavity.
On these moves and pass the air currents. Accordingly, there is an upper, middle nasal passage and lower (meatus). Each of them is formed by walls: the upper, inner, lateral outer, and lower, formed by the maxillary bones.
The upper two passages go to the sinuses, the lower - communicates with the orbit. The middle nasal passage leads to the maxillary sinuses. The strokes at the nose are narrow, the mucous membrane is richly equipped 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 - meatuscommunis.
Upper nasal passage
It takes the place between the middle and upper shells, is the shortest. Therefore, it is located, as it were, moved to the far part of the nasal cavity. It has holes in the posterior ethmoid cells. The main sinus of the nose, which is called the sphenoid , opens in it.
As the anatomical structure, the upper course 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, besides the olfactory nerve, also the nasal veins pass. The branches of the maxillary artery, which is the main artery supplying the nose and postganglionic fibers, from the pterygo-palatine node to innervate the glands of the nasal mucosa pass through the pterygo-palatine opening with the same fossa in the indicated nasal passage.
Middle nasal passage
Located between the middle and lower nasal concha of the ethmoid bone. It is longer and wider. The middle nasal passage is divided into the basal and sagittal parts. All sinuses (frontal and maxillary - maxillary sinuses) open here, except the main, middle and front cells of the ethmoid bone. The main function is the direction of air flow.
The middle nasal passage is still of more clinical importance due to communication with the frontal and maxillary caves. From here the sinus inflammation originates - sinusitis, ethmoiditis. Behind the middle nasal choana there is a wedge-palatine opening, through it there is a message of the pterygo-palatine fossa and the middle nasal passage. A wedge-palatine artery and nerves of the pterygo-palatine node — its nasal branches — pass through it into the nasal cavity.
Lower nasal passage
It is located above the hard palate (the bottom of the oral cavity) and the lower turbinate above. The outer wall of this passage is the lower part of the maxillary cave wall. In the anterior section of the lower nasal passage, a nasolacrimal canal with the duct of the same name opens. It begins in the orbit, which therefore also communicates with the lower nasal passage. This move is the widest and longest. The sinuses do not open in it.
In clinical ENT practice, the significance of this nasal passage is that it is used to puncture the maxillary sinus in the treatment of purulent sinusitis, as well as for the purpose of diagnosis.