- Paranasal sinuses
Paranasal sinuses Paranasal sinuses. 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.
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 maxillary sinuses, also called the maxillary antrechea and the largest of the paranasal sinuses, are under the eyes, in the maxillary bones.
- the frontal sinuses, superior to the eyes, in the frontal bone, which forms the hard part of the forehead.
- the ethmoid sinuses, which are formed from several discrete air cells within the ethmoid bone between the nose and the eyes.
- the sphenoid sinuses, in the sphenoid bone at the center of the skull base under the pituitary gland.
The paranasal air sinuses are lined with respiratory epithelium (ciliated pseudostratified columnar epithelium).
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.
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.
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.
- Paranasal+sinuses at eMedicine Dictionary
- The Anatomy Wiz: CT Paranasal Sinuses
- Sinus Problems FAQ
- Sinusitis: Symptoms, Causes, and Treatment
Head and neck, upper RT: Nose (TA A06.1, TH H3.05.01, GA 10.992) External nose Nasal cavityOpeningsLateral wallMedial wall Paranasal sinuses Naso-pharynx
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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