Sinus (anatomy)

Sinus is Latin for "bay", "pocket", "curve", or "bosom". In anatomy, the term is used in various contexts.

A sinus is a sack or cavity in any organ or tissue, or an abnormal cavity or passage caused by the destruction of tissue. In common usage, "sinus" usually refers to the paranasal sinuses, which are air cavities in the cranial bones, especially those near the nose and connecting to it. Each individual has four paired cavities located in the cranial bone or skull. These cavities are vitally important for a variety of reasons.

The word "sinusitis" is derived from sinus and is used to indicate that one or more of the membrane linings found in the sinus cavities has become inflamed or infected. It is however distinct from a fistula, which is a tract connecting two epithelialised surfaces. Any untreated infections occurring in the sinus cavities can affect the chest and lungs if left untreated.

Sinuses in the body

• Paranasal sinuses
  • Maxillary
  • Ethmoid
  • Sphenoid
  • Frontal
• Subcapsular sinus
• Medullary sinuses
• Trabecular sinuses
• Dural venous sinuses
  • Inferior sagittal
  • Superior sagittal
  • Straight
  • Occipital
  • Confluence of sinuses
  • Cavernous
  • Superior petrosal
  • Inferior petrosal
  • Transverse
  • Sigmoid
• Carotid sinus
• Renal sinus
• Coronary sinus

Sinusitis

If one or more of the paired paranasal sinuses or air cavities becomes inflamed, it leads to an infection called sinusitis. The term sinusitis means an inflammation of one or more of the sinus cavities. This inflammation causes an increase in internal pressure within these areas. The pressure is often experienced in the cheek area, eyes, nose, on one side of the head (temple areas), and can result in a severe headache.

The four paired sinuses or air cavities can be referred to as:

• Ethmoid sinus cavities which are located between the eyes.
• Frontal sinus cavities which can be found above the eyes (more in the forehead region).
• Maxillary sinus cavities are located on either side of the nostrils (cheekbone areas).
• Sphenoid sinuses that are located behind the eyes and lie in the deeper recesses of the skull.

When diagnosing a sinus infection, one can identify which sinus cavity the infection is located in by the term given to the cavity. Ethmoiditis refers to an infection in the ethmoid sinus cavity/ies, frontal sinusitis refers to an infection occurring in the frontal sinus cavity/ies, antritis is used to refer to an infection in the maxillary sinus cavity/ies whilst spenoiditis refers to an infection in the sphenoid sinus cavity/ies.

The Reason behind Sinus Cavities

The presence of sinus cavities within the cranial bone (skull) is essential for the following reasons:

• Sinus cavities allow for voice resonance (WebMD)
• They help filter and add moisture to any air that is inhaled through the nasal passages. On top of filtering and adding moisture to the air we inhale, they also help in the removal of unwanted particles from the sinus cavities (SinusWars)
• Sinus Cavities provide a means to lighten the overall weight of the skull.

Classification of a Sinus Infection (Sinusitis)

Sinusitis (a sinus infection) can be acute, chronic or recurrent.

• Acute Sinusitis: Any sinus infection which lasts for a maximum of three weeks can be referred to as acute sinusitis; with the affected individual displaying symptoms such as congestion, post nasal drip, halitosis (SinusWars), a runny nose as well as sinus pressure and pain in the affected areas.

• Chronic Sinusitis: This infection extends beyond the three week period and if left untreated can persist for years. Certain causes of chronic sinusitis can be allergies that have been left untreated, bacterial or fungal infections within one or more of the sinus cavities or any allergic disorders which targets and increases the sensitivity of the mucus membrane linings which surround the sinus cavities and nasal passages. Symptoms of chronic sinusitis are debilitating headaches, green colored mucus, severe nasal blockages or congestion and heavy pressure experienced in the cheek, forehead, temple and eye regions. Headaches may also be felt with chronic sinusitis.

• Recurrent Sinusitis: This type of sinus infection is intermittent; a person usually experiences this type of infection numerous times throughout a year with period of complete relief being experienced for weeks or months in-between.

Causes of Sinus Infections

A sinus infection can be caused by a variety of items. Untreated allergies are one of the main contributing factors to the development of sinus infections. A person with a sinus infection often has nasal congestion with thick nasal secretions, fever, and cough (WebMD). Patients can be treated by “reducing the swelling or inflammation in the nasal passages and sinuses, eliminating the infection, promoting drainage from the sinuses, and maintaining open sinuses” (WebMD). Sinusitis can be treated with medications and can also be eliminated by surgery.

Another cause of sinus infections is a result of bacterial invasions within one or more of the sinus cavities. Any bacteria that enters the nasal passages and sinus cavities through the air that is inhaled gets trapped by the mucus secreted by the mucous membranes surrounding these areas. These trapped particles can cause an irritation to these linings resulting in swelling and inflammation. “Bacteria that normally cause acute sinusitis are Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis (WebMD). These microorganisms, along with Staphylococcus aureus and some anaerobes (bacteria that live without oxygen), are involved in chronic sinusitis (WebMD).” Fungi can also cause chronic sinusitis.

Certain abnormalities or trauma related injuries to the nasal cavity can make it difficult for effective drainage of mucus from the sinus cavities. This mucus is then allowed to develop in these areas making the cavity an ideal area in which bacteria can both attach and thrive.

Outlook on Sinusitis

Sinusitis or sinus infections usually clear up if treated early and appropriately. Aside from those who develop complications, the outlook for acute bacterial sinusitis is good. People may develop chronic sinusitis or have recurrent attacks of acute sinusitis if they suffer with allergies or if they have any “structural or anatomical causes (SinusWars)” which predispose them to developing sinus infections.

Viral sinus infections do not however respond well to conventional treatments such as antibiotics.

When treating fungal sinusitis, an appropriate fungicide is usually administered.

References

"Sinusitis: Causes, Symptoms, Tests, and Treatment." WebMD - Better information. Better health. Web. 06 Nov. 2009. <http://www.webmd.com/a-to-z-guides/sinus-infection>.

“Sinus and Sinusitis Explained.” SinusWars, an extensive resource base for all sinus related information. Web. 13 Sept. 2011. <http://www.sinuswars.com>.

External Links

<http://www.sinuswars.com/sinus.asp>

<http://www.sinuswars.com/sinusitis.asp>

This anatomy article is a stub. You can help Wikipedia by expanding it.v · Categories: Anatomy Anatomy stubs Wikimedia Foundation. 2010. Игры ⚽ Поможем сделать НИР Ryan Guy United States Court of Private Land Claims Look at other dictionaries: Sinus — may refer to:In anatomy, where a sinus is a sac or cavity in any organ or tissue: *Sinus (anatomy), description of the general term *Anal sinuses, the furrows which separate the columns in the rectum *Paranasal sinuses, air cavities in the… …   Wikipedia Anatomy — • The science of the form and structure of living beings Catholic Encyclopedia. Kevin Knight. 2006. Anatomy     Anatomy     † …   Catholic encyclopedia Sinus urogenitalis — eines weiblichen Embryos in der 8,5 bis 9. Woche (aus Gray s Anatomy) Der Sinus urogenitalis ist eine embryologische Vorläuferstruktur verschiedener Harn und Geschlechtsorgane. Beim menschlichen Embryo gibt es bis zur 5. Entwicklungswoche noch… …   Deutsch Wikipedia sinus of Valsalva — sinus of Val·sal·va väl säl və n any one of the pouches of the aorta and pulmonary artery which are located behind the flaps of the semilunar valves and into which the blood in its regurgitation toward the heart enters and thereby closes the… …   Medical dictionary sinus — ► NOUN Anatomy & Zoology ▪ a cavity within a bone or other tissue, especially one in the bones of the face or skull connecting with the nasal cavities. ORIGIN Latin, a recess, bend …   English terms dictionary sinus — sinuslike, adj. /suy neuhs/, n., pl. sinuses. 1. a curve; bend. 2. a curving part or recess. 3. Anat. a. any of various cavities, recesses, or passages, as a hollow in a bone, or a reservoir or channel for venous blood. b. one of the hollow… …   Universalium Sinus paranasal — Pour les articles homonymes, voir Sinus. Sinus paranasal Sinus paranasaux …   Wikipédia en Français Sinus venosus — This article is on an embryological structure. For the heart defect of the same name, please see atrial septal defect. Infobox Embryology Name = Sinus venosus Latin = GraySubject = 138 GrayPage = 528 Caption = Interior of dorsal half of heart… …   Wikipedia sinus — 1. [TA] A channel for the passage of blood or lymph, without the coats of an ordinary vessel; e.g., blood passages in the gravid uterus or those in the cerebral meninges. 2. [TA] A cavity or …   Medical dictionary sinus — [ sʌɪnəs] noun 1》 Anatomy & Zoology a cavity within a bone or other tissue, especially one in the bones of the face or skull connecting with the nasal cavities. 2》 Anatomy & Zoology an irregular venous or lymphatic cavity, reservoir, or dilated… …   English new terms dictionary 18+ © Academic, 2000-2024 Contact us: Technical Support, Advertising Dictionaries export, created on PHP, Joomla, Drupal, WordPress, MODx. Mark and share Search through all dictionaries Translate… Search Internet Share the article and excerpts Direct link … Do a right-click on the link above and select “Copy Link”