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四對鼻竇

每個人都有四對鼻竇，根據(jù)所在的頭骨部位而命名。這四對鼻竇的名稱分別是：

上頜竇（Maxillary Sinuses）：位于眼睛之下的上頷骨，是四對鼻竇中體積最大的一對。

額竇（frontal Sinuses）：位于眼睛之上的額骨。

篩竇（ethmoid Sinuses）：位于眼睛和鼻之間的篩骨，并向后通往頭顱。

蝶竇（sphenoid Sinuses）：位于頭顱骨底部的中心。

這四對鼻竇于頭的左右側(cè)各一，共八個。

結(jié)構(gòu)

Humans possess four paired paranasal sinuses, divided into subgroups that are named according to thebones within which the sinuses lie:

The maxillary sinus （ 英語 ： maxillary sinus ） es, the largest of the paranasal sinuses, are under theeyes, in the maxillary bones (open in the back of the semilunar hiatus （ 英語 ： semilunar hiatus ） of the nose). They are innervated by thetrigeminal nerve.

Thefrontal sinuses, superior to the eyes, in thefrontal bone, which forms the hard part of theforehead. They are also innervated by thetrigeminal nerve.

The ethmoidal sinus （ 英語 ： ethmoid sinus ） es, which are formed from several discrete air cells within theethmoid bonebetween the nose （ 英語 ： human nose ） and the eyes. They are innervated by the ethmoidal nerves （ 英語 ： ethmoidal nerves ） , which branch from the nasociliary nerve （ 英語 ： nasociliary nerve ） of thetrigeminal nerve.

The sphenoidal sinus （ 英語 ： sphenoid sinus ） es, in thesphenoid bone. They are innervated by the trigeminal nerve.

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

作用

醫(yī)學(xué)界對鼻竇在人體內(nèi)的作用還未很清楚。不過，下列各項原因都有可能：

減輕頭顱骨前方的重量

幫助令吸入的空氣在到達(dá)肺部之前，可以更溫暖和濕潤

幫助增強(qiáng)發(fā)聲時的共鳴

當(dāng)臉部受到襲擊時，可以當(dāng)作一個力量的緩沖區(qū)

功能

  Lateral projection of the paranasal sinuses as seen in an X-ray image

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 thevoice.

Providing a buffer against facial trauma.

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.

Regulation of intranasal and serum gas pressures.

Immunological defense.

鼻竇炎

鼻竇由很多稱為 竇口 （ 英語 ： Sinus ostia ） 的小管連往鼻腔。不過當(dāng)人因?yàn)槠胀ǜ忻岸卤茄谆虮悄つ[脹，都會使這些小管閉塞。當(dāng)這些小管閉塞時，就會影響到鼻腔黏液滯流在鼻竇內(nèi)，影響排放。如果不及早診治，就會演變成為鼻竇炎。

Inflammation

The paranasal sinuses are joined to thenasal cavityvia small orifices called ostia （ 英語 ： sinus ostia ） . These become blocked easily by allergic inflammation, or by swelling in the nasal lining that occurs with acold. If this happens, normal drainage ofmucuswithin the sinuses is disrupted, andsinusitismay occur. Because the maxillary posterior teeth are close to the maxillary sinus, this can also cause clinical problems if any disease processes are present, such as an infection in any of these teeth. These clinical problems can include secondary sinusitis, the inflammation of the sinuses from another source such as an infection of the adjacent teeth.

These conditions may be treated with drugs such as decongestant （ 英語 ： decongestant ） s, which cause vasoconstriction in the sinuses; reducing inflammation; by traditional techniques ofnasal irrigation; or bycorticosteroid.

Development

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

The results of experimental studies suggest that the natural ventilation-rate of a sinus with a single sinus ostium （ 英語 ： sinus ostium ） (opening), is extremely slow. Such limited ventilation may be protective for the sinus, as it would help prevent drying of its mucosal surface and maintain a near-sterile environment with highcarbon dioxideconcentrations and minimalpathogenaccess. Thus composition of gas content in the maxillary sinus is similar tovenous blood, with high carbon dioxide and loweroxygenlevels compared to breathing air.

Clinical relevance

Cancer

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 thansarcomas. Metastases are rare.Tumours of the sphenoid and frontal sinuses are extremely rare.

歷史

詞源

Sinus is aLatinword meaning a "fold", "curve", or "bay".

其他動物

Paranasal sinuses occur in many other animals, including most哺乳動物、鳥、non-avian恐龍和鱷目。The bones occupied by sinuses are quite variable in these other species.

圖片

Paranasal sinuses

參見

本條目使用了部分解剖術(shù)語，概述請參閱 這里 （ 英語 ： anatomical terminology ） 。

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