disorders of the nose

Anatomy of the nose and paranasal sinuses

The nasal cavity consists of two channels separated by osteo-cartilage of the nasal septum. They communicate with the outside through the nostrils and open up to the back in the nasopharynx at the center of the choanae.

The side wall of the nasal cavities has an irregular surface: It actually has 3 sheets of bone (sometimes 4) covered with mucous membrane. Each nasal cavity will have a lower, center, and upper nostril and sometimes a top nostril.

The spaces under the nostrils are called meati, which are where the paranasal sinuses transmit signals.

The paranasal sinuses are pneumatic facial mass cavities that develop during the first few years of life and are consistent with the nasal drops. They include:

  • jaw sinuses, two large symmetrical cavities located below the orbits;
  • frontal sinuses, of irregular shape, are included in the thickness of the frontal bone above the root of the nose;
  • sphenoid sinuses, two cubic cavities located within the body of the sphenoid;
  • ethmoidal cells, a complex system of small cavities that form the two ethmoid labyrinths.

Functions of the nose and the paranasal sinuses

The nose has a number of functions:

  • respiratory function, the nose regulates the airflow through highly sophisticated central control systems that provide the right oxygen content according to the different needs of the body;
  • function of heating and humidifying the air breathed in through an efficient vascularized siphon system which, depending on the air temperature, can increase or decrease the volume. Dilution enables more heat and higher moisture content. Their reduction, on the other hand, allows for greater air transfusion as it makes the nasal passage larger;
  • olfactory function, enabled by a specific epithelium (neuro-epithelium) located on the turn of each nasal passage;
  • defensive function, through a series of systems that provide a barrier against bulky particles, microparticles and pathogenic microorganisms;
  • Voice resonance function, especially when speaking in certain phonemes.

Several hypotheses have been made on the function of paranasal sinuses:

  • lightening the skull that would otherwise weigh too much;
  • protection of the skull base in case of trauma;
  • thermal insulation against more noble structures;
  • resonance in voice output.
Patologie del naso
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