Human bays are spaces filled with air that are located inside the skull. There are four types of them: maxillary sinuses, frontal sinuses, ethmoid sinuses and sphenoid sinuses. What are the functions of the sinuses? In addition to the well-known sinusitis, what diseases can the paranasal sinuses be affected? What treatments are used for the most common sinus conditions?

The sinuses(paranasal sinuses) are structures inside the facial skeleton that connect directly to the nasal cavity. There are four different types of them, but the structure of each of the paranasal sinuses is similar.

Zatoki: construction

The sinuses are actually invaginations of the mucosa (which originate in the nasal cavity) into the various structures of the facial skeleton. They are mostly filled with air, except for it - under normal conditions - there is also a small amount of secretion in the sinuses.

The mucosa that lines the sinuses is normally pink in color. There are four different types of cells within it. They are:

  • ciliated support cells
  • cilia free support cells
  • goblet cells
  • base cells

Zatoki: development

The first processes related to the formation of sinuses occur very early, already in the first stages of fetal life. However, they last for a long time: the development of the sinuses continues for many years after birth, until they reach their final dimensions and shape in the second decade of human life.

Bays: types

In humans, there are four pairs of different sinuses. They are:

  • maxillary sinuses: the largest of all paranasal sinuses, they are located below the eyes (more strictly within the jawbones) and connect to the nasal cavity through the semilunar hiatus, the average volume of each of the maxillary sinuses is approximately 24 cm 3
  • frontal sinuses: located above the eyes (within the frontal bones), connected to the nasal cavity via the fronto-nasal canal, the capacity of one frontal sinus usually ranges from 8 to 23 cm3
  • ethmoid cells: a group of several different air structures located within the ethmoid bone, they extend between the eyes and the nose, they communicate with the nasal cavity, e.g. withwith a semilunar hiatus
  • sphenoid sinuses: they are located within the sphenoid bone, they leave the top part of the nasal cavity, the volume of a single sphenoid sinus is about 3 cm3

Zatoki: role

The function of the paranasal sinuses has already been wondered by many different researchers. However, it was not clear what these structures were responsible for. Potential sinus functions could be:

  • heating and moisturizing the air that enters the body through the nose
  • participation in the reception of olfactory stimuli
  • protection of head structures against injuries
  • participation in the processes of thermal insulation of the skull structures
  • reduction of craniofacial weight
  • participation in creating and receiving other people's speech

Inflammation is the most common sinus disease

The diseases that may involve these structures are much better known than the function of the sinuses. The most famous of these is the inflammation of the paranasal sinuses.

Sinusitis may be caused by an infection (viral, bacterial or fungal) or an allergy. Hormonal disorders and side reactions after taking various medications (rhinitis) may also contribute to this problem.

There are two types of this disease:

  • acute sinusitis (lasting up to 3 weeks)
  • chronic sinusitis (lasting more than 3 weeks)

The primary symptoms of sinusitis are:

  • pain complaints located within the head (in different places depending on which sinuses are affected - e.g. pain in the forehead may indicate inflammation of the frontal sinus)
  • face hypersensitivity to touch or pressure
  • nasal obstruction

In addition to those mentioned, sinusitis may also be associated with an increase in body temperature, changes in the sense of smell, the occurrence of pain after adopting specific body positions (e.g. the appearance of a headache when tilting it), and the flow of secretions down the back of the throat.

sinuses: other diseases

Apart from inflammation, the sinuses may also develop other diseases. Among them, it is worth mentioning, for example, polyps of the paranasal sinuses. They appear when the lining of the sinuses is enlarged. Sinusitis can contribute to the development of polyps, but also allergic diseases, asthma and cystic fibrosis.

Another sinus related medical condition is sinus cysts. Their formation is favored primarily by the presence of thick mucus inside the sinuses. Evenfor a long time, sinus cysts may be completely asymptomatic. After some time, however, they can lead to the appearance of similar ailments as in the case of sinusitis.

Neoplasms can also develop within the sinuses. However, these are extremely rare situations. Of all the cases of malignant neoplasms, those located within the sinuses account for less than 1%. Sinus cancer occurs mainly in patients between the ages of 40 and 70, and men are more likely to develop them.

Sinuses: tests performed when sinus diseases are suspected

In a situation where a patient reports to a doctor with symptoms suggestive of sinus disease, an ENT examination is of primary importance. During the examination, the most important thing is rhinoscopy, i.e. endoscopy of the nasal cavity. This can be done with the use of a classic, metal speculum, as well as with the use of an endoscope (which allows for better visualization of possible pathologies).

When there is a suspicion that a patient has polyps or sinus cysts, it may be appropriate to perform sinus imaging, such as computed tomography or magnetic resonance imaging.

If you suspect a patient's sinus problem is due to an infection, a sample of the patient's sinus fluid may be collected. It is passed on for microbiological tests, which can lead to the determination of the exact infection in the patient, as well as the selection of the appropriate treatment.

Sinuses: treatment of sinus diseases

In the treatment of sinus diseases, pharmacotherapy and specialist treatments can be used. In the case of the former, the patient may be prescribed antibiotics (in bacterial sinusitis) or drugs that reduce the production of secretions (i.e. substances that constrict blood vessels in the nasal cavity and sinuses, such as, for example, oxymetazoline).

In addition to sinus diseases, inhalations with the use of various substances (e.g. natural essential oils), intranasal preparations of glucocorticosteroids, antihistamines or hypertonic sea s alt solutions are also used.

However, just as acute sinusitis can be cured with pharmacotherapy, other interventions must be implemented in patients with polyps, sinus cysts, or chronic sinusitis.

In case of such problems, it may be necessary to undergo surgery. An example of a sinus surgery is functional endoscopic sinus surgery.

During it, it is possible, for example, to deleteexisting in the patient's sinus polyps, but also the widening of the orifices of individual of these structures (which may lead to the improvement of the condition of patients with chronic sinusitis).

Sources:

  1. Human anatomy. A textbook for students and doctors, ed. II and supplemented by W. Woźniak, ed. Urban & Partner, Wrocław 2010
  2. Ameet Singh, Paranasal Sinus Anatomy, Dec 08, 2022, Medscape; on-line access: https://emedicine.medscape.com/article/1899145-overview
  3. Glen T. Porter, Francis B. Quinn, Paranasal Sinuses: Anatomy and Function, The University of Texas Medical Branch Department of Otolaryngology Galveston, Texas Grand Rounds Presentation January 2002

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ENT