Paranasal sinuses


Paranasal sinuses
Paranasal sinuses
Nnh front.svg
Paranasal sinuses.
X-Ray Skull.jpg
Lateral projection of the paranasal sinuses
Latin sinus paranasales
Gray's subject #223 998
Dorlands/Elsevier Paranasal sinuses

Paranasal sinuses are a group of four paired air-filled spaces that surround the nasal cavity (maxillary sinuses), above and between the eyes (ethmoid sinuses and frontal sinuses), and behind the ethmoids (sphenoid sinuses). The sinuses are named for the facial bones behind which they are located.

Contents

Types in humans

Humans possess a number of paranasal sinuses, divided into subgroups that are named according to the bones within which the sinuses lie:

The paranasal air sinuses are lined with respiratory epithelium (ciliated pseudostratified columnar epithelium).

Development

Paranasal sinuses form developmentally through excavation of bone by air-filled sacs (pneumatic diverticula) from the nasal cavity. This process begins prenatally, and it continues through the course of an organism's lifetime.

Sinuses in animals

Paranasal sinuses occur in a variety of animals (including most mammals, birds, non-avian dinosaurs, and crocodilians). In non-humans, the bones occupied by sinuses are quite variable.

Biological function

The biological role of the sinuses is debated, but a number of possible functions have been proposed:

  • Decreasing the relative weight of the front of the skull, and especially the bones of the face.
  • Increasing resonance of the voice.
  • Providing a buffer against blows to the face.
  • Insulating sensitive structures like dental roots and eyes from rapid temperature fluctuations in the nasal cavity.
  • Humidifying and heating of inhaled air because of slow air turnover in this region.

Ailments

The paranasal sinuses are joined to the nasal cavity via small orifices called ostia. These become blocked easily by allergic inflammation, or by swelling in the nasal lining which occurs with a cold. If this happens, normal drainage of mucus within the sinuses is disrupted, and sinusitis may occur.

These conditions may be treated with drugs such as pseudoephedrine, which causes vasoconstriction in the sinuses, reducing inflammation, by traditional techniques of nasal irrigation, or by corticosteroid.

Malignancies of the paranasal sinuses comprise approximately 0.2% of all malignancies. About 80% of these malignancies arise in the maxillary sinus. Men are much more often affected than women. They most often occur in the age group between 40 and 70 years. Carcinomas are more frequent than sarcomas. Metastases are rare. Tumours of the sphenoid and frontal sinuses are extremely rare.

Etymology

Sinus is a Latin word meaning a fold or pocket; in particular the front pocket in a toga.

Additional images

External links


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Look at other dictionaries:

  • paranasal sinuses — the air filled spaces, lined with mucous membrane, within some of the bones of the skull. They open into the nasal cavity, via the meatuses, and are named according to the bone in which they are situated. They comprise the frontal sinuses and the …   Medical dictionary

  • paranasal sinuses — the air filled spaces, lined with mucous membrane, within some of the bones of the skull. They open into the nasal cavity, via the meatuses, and are named according to the bone in which they are situated. They comprise the frontal sinuses and the …   The new mediacal dictionary

  • Пазухи Носа Придаточные (Paranasal Sinuses) — заполненные воздухом пространства, расположенные в некоторых костях черепа, которые изнутри выстланы слизистой оболочкой; их названия соответствуют тем костям, внутри которых они расположены. Эти пространства открываются в носовую полость через… …   Медицинские термины

  • paranasal sinus — One of many small hollow spaces in the bones around the nose. Paranasal sinuses are named after the bones that contain them: frontal (the lower forehead), maxillary (cheekbones), ethmoid (beside the upper nose), and sphenoid (behind the nose).… …   English dictionary of cancer terms

  • paranasal — Alongside the nose. * * * para·na·sal nā zəl adj adjacent to the nasal cavities esp of, relating to, or affecting the paranasal sinuses <paranasal pain> * * * para·na·sal (par″ə naґzəl) alongside or near the nose …   Medical dictionary

  • paranasal sinus and nasal cavity cancer — Cancer that forms in tissues of the paranasal sinuses (small hollow spaces in the bones around the nose) or nasal cavity (the inside of the nose). The most common type of paranasal sinus and nasal cavity cancer is squamous cell carcinoma (cancer… …   English dictionary of cancer terms

  • paranasal sinus — n any of various sinuses (as the maxillary sinus and frontal sinus) in the bones of the face and head that are lined with mucous membrane derived from and continuous with the lining of the nasal cavity …   Medical dictionary

  • paranasal sinus — noun any of the paired sinuses in the bones of the face adjacent to the nasal cavity that are lined with mucous membrane that is continuous with the lining of the nasal cavities • Syn: ↑sinus paranasales, ↑nasal sinus • Hypernyms: ↑sinus * * *… …   Useful english dictionary

  • paranasal sinus — noun A number of air filled spaces, or sinuses, within the bones of the skull and face. Syn: sinus paranasales …   Wiktionary

  • Sinus paranasal — Pour les articles homonymes, voir Sinus. Sinus paranasal Sinus paranasaux …   Wikipédia en Français


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