Sinusitis
Sinusitis
Definition
Sinusitis is an inflammation of the sinuses, which are airspaces within the bones of the face. Sinusitis is most often due to an infection within these spaces.
Description
The sinuses are paired air pockets located within the bones of the face. There are:
- the frontal sinuses, located above the eyes, in the center region of each eyebrow
- the maxillary sinuses, located within the cheekbones, just to either side of the nose
- the ethmoid sinuses, located between the eyes, just behind the bridge of the nose
- the sphenoid sinuses, located just behind the ethmoid sinuses, and behind the eyes.
The sinuses are connected with the nose. They are lined with the same kind of skin found elsewhere within the respiratory tract. This skin has tiny little hairs projecting from it called cilia. The cilia beat constantly to help move the mucus produced in the sinuses into the respiratory tract. The beating cilia sweeping the mucus along the respiratory tract helps to clear the respiratory tract of any debris or of any organisms that may be present. When the lining of the sinuses is at all swollen, the swelling interferes with the normal flow of mucus. Trapped mucus can then fill the sinuses, causing an uncomfortable sensation of pressure and providing an excellent environment for the growth of infection-causing bacteria.
Demographics
It is estimated that about 37 million Americans are affected by sinusitis each year. Having a cold increases the chance of getting sinusitis. Immune system disorders also increase this likelihood. Children with asthma are also considered more likely to be affected by sinusitis.
Causes and symptoms
Sinusitis is usually due to an infection, although swelling from allergies can mimic the symptoms of pressure, pain , and congestion, and allergies can set the stage for a bacterial infection. Bacteria are the most common cause of sinus infection. Streptococcus pneumoniae causes about 33 percent of all cases, while Haemophilus influenzae causes about 25 percent of all cases. Sinusitis in children may be caused by Moraxella catarrhalis (20%). In people with weakened immune systems (including patients with diabetes, acquired immunodeficiency syndrome or AIDS , and patients who are taking medications that lower their immune resistance, such as cancer and transplant patients), sinusitis may be caused by fungi such as Aspergillus, Candida, or Mucorales.
Acute sinusitis usually follows some type of upper respiratory tract infection or cold. Instead of ending, the cold seems to linger on, with constant or even worsening congestion. Drainage from the nose often changes from a clear color to a thicker, yellowish-green. The individual may develop a fever . Headache and pain over the affected sinuses may occur, as well as a feeling of pressure that may worsen when the patient bends over. There may be pain in the jaw or teeth. Some children, in particular, get upset stomachs from the infected drainage going down the back of their throats and being swallowed. Some patients develop a cough .
Chronic sinusitis occurs when the problem has existed for at least three months. There is rarely a fever with chronic sinusitis. Sinus pain and pressure are frequent, as is nasal congestion. Because of the swelling in the sinuses, they may not be able to drain out the nose. Drainage, therefore, drips constantly down the back of the throat, resulting in a continuously sore throat and bad breath.
When to call the doctor
If the child is displaying the signs of sinusitis for more than a few days, the doctor should be contacted. If a cold seems to be getting better and then gets worse again, it may have developed into sinusitis. Likewise, colds that linger beyond a week may indicate sinusitis, and the doctor should be called.
Diagnosis
Diagnosis is sometimes tricky, because the symptoms so often resemble those of an uncomplicated cold. However, sinusitis should be strongly suspected when a cold lingers beyond about a week's time.
Medical practitioners have differing levels of trust in certain basic examinations commonly conducted in the office. For example, tapping over the sinuses may cause pain in patients with sinusitis, but it may not. A procedure called "sinus transillumination" may or may not also be helpful. Using a flashlight pressed up against the skin of the cheek, the practitioner will look in the patient's open mouth. When the sinuses are full of air (under normal conditions), the light will project through the sinus and will be visible on the roof of the mouth as a lit-up, reddened area. When the sinuses are full of mucus, the light will be stopped. While this simple test can be helpful, it is certainly not a perfect way to diagnose or rule out the diagnosis of sinusitis.
X-ray pictures and CT scans of the sinuses are helpful for both acute and chronic sinusitis. People with chronic sinusitis should also be checked for allergies, and they may need a procedure called nasal endoscopy where a very slender lighted fiber optic tube is placed in the nose in order for the doctor to see if any kind of anatomic obstruction is causing the illness. For example, the septum (the cartilage which separates the two nasal cavities from each other) may be slightly displaced (a deviated septum). This condition can result in chronic obstruction, setting the person up for the development of an infection.
Treatment
Antibiotic medications are used to treat acute sinusitis. Suitable antibiotics include sulfa drugs, amoxicillin, and a variety of cephalosporins. These medications are usually given for about two weeks but may be given for even longer periods. Decongestants or the short-term use of decongestant nose sprays can be useful. Acetaminophen (Tylenol) and ibuprofen (Motrin, Advil) can decrease the pain and headache associated with sinusitis. Also, running a humidifier can prevent mucus within the nasal passages from drying out uncomfortably and can help soothe any accompanying sore throat or cough.
Chronic sinusitis is often treated initially with antibiotics. Steroid nasal sprays may be used to decrease swelling in the nasal passages. If an anatomic reason is found for chronic sinusitis, it may need to be corrected with surgery. If a surgical procedure is necessary, samples are usually taken at the same time to allow identification of any organisms present which may be causing infection.
Fungal sinusitis requires surgery to clean out the sinuses. Then, a relatively long course of a very strong antifungal medication called amphotericin B is given through a needle in the vein (intravenously).
Alternative treatment
Some practitioners believe that chronic sinusitis is associated with food allergies . These doctors would suggest an elimination/challenge diet to identify and eliminate allergenic foods. While linking chronic sinusitis to food is widely considered controversial, many practitioners link the problem to aero-allergies. Irrigating the sinuses with a salt-water solution is thus recommended for sinusitis and allergies, in order to clear the nasal passages of mucus. Another solution for nasal lavage (washing) uses powdered goldenseal (Hydrastis canadensis ). Other herbal treatments, taken internally, include a mixture made of eyebright (Euphrasia officinalis ), goldenseal, yarrow (Achillea millefolium ), and horseradish, or, when infection is present, a mixture made of echinacea (Echinacea spp.), wild indigo, and poke root (Phytolacca decandra-Americana ).
Homeopathic practitioners find a number of remedies useful for treating sinusitis. Among those they recommend are: Arsenicum album, Kalium bichromium, Nux vomica, Mercurius iodatus, and Silica.
Acupuncture has been used to treat sinusitis, as have a variety of dietary supplements, including vitamins A, C, and E, and the mineral zinc. Contrast hydrotherapy (hot and cold compresses, alternating three minutes hot, 30 seconds cold, repeated three times always ending with cold) applied directly over the sinuses can relieve pressure and enhance healing. A direct inhalation of essential oils (two drops of oil to two cups of water) using thyme, rosemary, and lavender can help open the sinuses and kill bacteria that cause infection.
Prognosis
Prognosis for sinus infections is usually excellent, although some individuals may find that they are particularly prone to contracting such infections after a cold. Fungal sinusitis, however, has a relatively high death rate.
Prevention
Prevention involves the usual standards of good hygiene to cut down on the number of colds an individual catches. Avoiding exposure to cigarette smoke, identifying and treating allergies, and avoiding deep dives in swimming pools may help prevent sinus infections. During the winter, it is a good idea to use a humidifier. Humidifiers should be adequately and frequently cleaned with bleach or comparable cleanser to avoid mold which can be aerosolized and then exacerbate existing allergies. Dry nasal passages may crack, allowing bacteria to enter. When allergies are diagnosed, a number of nasal sprays are available to assist in preventing inflammation within the nasal passageways, thus allowing the normal flow of mucus.
Parental concerns
Sinusitis can usually be treated successfully with antibiotics. It can, however, be very dangerous or even fatal if left untreated it becomes progressively worse such that the infection spreads.
KEY TERMS
Cilia —Tiny hairlike projections on certain cells within the body. Cilia produce lashing or whipping movements to direct or cause motion of substances or fluids within the body. Within the respiratory tract, the cilia act to move mucus along, in an effort to continually flush out and clean the respiratory tract.
Sinus —A tubular channel or cavity connecting one body part with another or with the outside. Often refers to one of the air-filled cavities surrounding the eyes and nose that are lined with mucus-producing membranes. They cleanse the nose, add resonance to the voice, and partially determine the structure of the face.
See also Allergic rhinitis.
Resources
BOOKS
Bruce, Debra Fulghum, et al. The Sinus Cure: 7 Steps to Relieve Sinusitis and Other Ear, Nose, and Throat Conditions. Westminster, MD: Ballantine Books, 2001.
Chronic Sinusitis: A Medical Dictionary, Bibliography, and Annotated Research Guide to Internet Sources. San Diego, CA: Icon Group International, 2004.
Hirsch, Alan R. What Your Doctor May Not Tell You about Sinusitis: Relieve Your Symptoms and Identify the Source of Your Pain. Boston, MA: Warner Books, 2004.
Kavuru, Mani S., et al. Diagnosis and Management of Rhinitis and Sinusitis, 2nd ed. Cleveland, OH: Professional Communications, 2001.
Kenned, David W., et al. Living with Chronic Sinusitis: A Patient's Guide to Sinusitis, Nasal Allergies, Polyps, and Their Treatment Options. Long Island City, NY: Hatherleigh Co., 2004.
Plasse, Harvey, et al. Sinusitis Relief. New York: Henry Holt & Co., 2002.
PERIODICALS
Glaser, Gabrielle. "How to Spot a Sinus Infection." Parents Magazine 75 (March 2000): 89–93.
ORGANIZATIONS
American Academy of Allergy, Asthma and Immunology. 611 East Wells Street, Milwaukee, WI 53202. Web site: <www.aaaai.org>.
American Academy of Otolaryngology-Head and Neck Surgery Inc. One Prince Street, Alexandria, VA 22314–3357. Web site: <www.entnet.org>.
Joint Council of Allergy, Asthma, and Immunology. 50 N. Brockway, Suite 3.3, Palatine, IL 60067. Web site: <www.jcaai.org>.
WEB SITES
"Sinusitis." National Institute of Allergy and Infectious Diseases, April 2002. Available online at <www.niad.nih.gov/factsheets/sinusitis.htm> (accessed November 15, 2004).
Helen Davidson Rosalyn Carson-DeWitt, MD
Sinusitis
Sinusitis
Are There Different Types of Sinusitis?
What Are the Symptoms of Sinusitis?
Sinusitis (sy-nyoo-SY-tis) is an inflammation of the sinuses (SY-nuh-ses), the hollow chambers or cavities located in the bones of the face that surround the nose.
KEYWORDS
for searching the Internet and other reference sources
Allergies
Asthma
Paranasal sinuses
Respiratory infections
Sinuses
Streptococcus pneumoniae
What Causes Sinusitis?
There are four pairs of paranasal sinuses (the sinuses surrounding the nose):
- The frontal sinuses are in the forehead and over the eyebrows.
- The ethmoid (ETH-moyd) sinuses are between the eyes at the bridge of the nose.
- The sphenoid (SFEE-noyd) sinuses are behind the ethmoid sinuses.
- The maxillary (MAX-ih-lary) sinuses are in the cheekbones.
The sinuses and the narrow tube-like structures that link them to the nasal passages are lined with the same mucous membranes* that line the nose. Colds, allergies, and exposure to some chemicals can cause swelling and inflammation in the lining of the sinus passages and block sinus drainage. Bacteria (such as Streptococcus pneumoniae, strep-tuh-KAH-kus
- *mucous membranes
- are the moist linings of the mouth, nose, eyes, and throat.
nu-MO-nye), viruses, and fungi that live in the body may become trapped, multiply, and invade the inflamed sinuses.
People with allergies, asthma, and cystic fibrosis* are more likely to have sinus infections. So are people with a weakened immune system, such as those who have AIDS or cancer; people with narrow sinus passages or with growths or blockages in the nasal area, such as tumors or polyps*; and people with previously broken or deformed nasal bones. The risk of sinusitis also is higher when people swim or dive, because of the pressure this activity puts on the sinus cavities.
- *cystic fibrosis
- (SIS-tik fy-BRO-sis) is a disease that causes the body to produce thick mucus that clogs passages in many of the body’s organs, including the lungs.
- *polyps
- (PAH-lips) are bumps or growths usually on the lining or surface of a body part (such as the nose or intestine). Their size can range from tiny to large enough to cause pain or obstruction. They may be harmless, but they also may be cancerous.
Are There Different Types of Sinusitis?
Physicians classify sinusitis in three ways:
- Acute* sinusitis often develops after a person has had a cold, with symptoms lasting less than 3 weeks.
- Chronic* sinusitis can last 3 to 8 weeks or longer; it often occurs in people who have allergies or asthma.
- Recurrent sinusitis consists of several acute episodes of sinusitis in 1 year.
- *acute
- describes an infection or other illness that comes on suddenly and usually does not last very long.
- *chronic
- (KRAH-nik) means continuing for a long period of time.
How Common Is Sinusitis?
The National Institute of Allergy and Infectious Diseases estimates that every year 37 million people in the United States have sinusitis.
Is Sinusitis Contagious?
No one can catch a sinus infection from another person, but the viruses and bacteria that cause colds and other respiratory tract* infections that can trigger sinusitis may spread from person to person in drops of fluid from the nose or mouth. When people cough, sneeze, laugh, or talk, they can transmit germs to their hands, to the surfaces around them, and into the air. Other people can breathe in the germs or touch contaminated surfaces with their hands and spread the germs to their noses and mouths.
- *respiratory tract
- includes the nose, mouth, throat, and lungs. It is the pathway through which air and gases are transported down into the lungs and back out of the body.
What Are the Symptoms of Sinusitis?
Symptoms of a cold (runny nose and low fever) often give way to pain and pressure in the sinuses, which are usually the first signs of sinusitis. Other symptoms include pain or puffiness around the eyes; a bad-smelling, yellow-green discharge from the nose; bad breath; a headache in the morning; aching in the upper jaw and the back teeth; weakness or extreme tiredness; and coughing, especially at night. People with sinusitis occasionally develop earaches, neck pain, or a sore throat caused by mucus* draining into the throat.
- *mucus
- (MYOO-kus) is a thick, slippery substance that lines the insides of many body parts.
How Is Sinusitis Diagnosed?
Sinusitis is suspected if cold symptoms last for more than 10 days or if sinusitis symptoms are present. A doctor may order X rays or a computerized tomography* (CT) scan to determine whether the sinuses are inflamed.
- *computerized tomography
- (kom-PYOO-ter-ized toe-MAH-gruh-fee) or CT, also called computerized axial tomography (CAT), is a technique in which a machine takes many X rays of the body to create a three-dimensional picture.
How Is Sinusitis Treated?
Bacterial sinusitis usually clears up after treatment with antibiotics. There is no specific treatment for sinusitis caused by a virus. People can try to relieve the symptoms of sinusitis in several ways. They can take acetaminophen* to help ease the pain and use nonprescription decongestants (deekon-JES-tents), taken by mouth or in sprays, to lessen stuffiness. Using a decongestant nasal spray for more than a few days, however, may itself cause swelling of the sinuses and slow recovery. Saline or salt sprays also may reduce swelling in the sinuses. Placing a warm compress over the infected sinuses, using a steam vaporizer*, or sitting in a warm, steamy bathroom can help as well. Doctors may prescribe special nasal sprays or oral (by mouth) medications for people with chronic sinusitis who have allergies that contribute to the infection. In some cases, people with severe chronic sinusitis may undergo surgery to enlarge their sinus passages, to remove a polyp, or to fix a deviated septum* that might be blocking sinus drainage.
- *acetaminophen
- (uh-see-the-MIH-noh-fen) is a medication commonly used to reduce fever and relieve pain.
- *vaporizer
- is a device that converts water (or a liquid medication) into a vapor, a suspension of tiny droplets that hang in the air and can be inhaled.
- *deviated septum
- is a condition in which the wall of tissue between the nasal passages, the septum, divides the passageways unevenly, sometimes causing breathing difficulties and blockage of sinus drainage.
How Long Will It Last?
Acute sinusitis usually clears up within 3 weeks, or within 1 to 2 weeks with treatment. Chronic sinusitis lasts 3 to 8 weeks or longer and may require longer courses of antibiotics and other treatments to resolve the condition.
Are There Complications?
Complications of sinusitis are rare, although they do occur. Sinusitis can cause osteomyelitis* when the infection from the sinus spreads into the bones of the face or skull, or it can lead to an infection of brain tissue or meningitis (inflammation of the meninges*). A sinus infection also can spread to invade the tissues surrounding the eyes.
- *osteomyelitis
- (ah-stee-o-my-uh-LYE-tis) is a bone infection that is usually caused by bacteria. It can involve any bone in the body, but it most commonly affects the long bones in the arms and legs.
- *meninges
- (meh-NIN-jeez) are the membranes that enclose and protect the brain and the spinal cord.
Can Sinusitis Be Prevented?
Because there is no practical way to prevent all colds or to eliminate all allergies, sinusitis is not entirely preventable. People can limit their exposure to the viruses and bacteria that cause the infections by washing their hands thoroughly and frequently and by not sharing eating or drinking utensils. Not smoking and avoiding exposure to tobacco smoke also can help limit the risk of sinusitis. It is wise for people with allergies to avoid the things that trigger their allergy symptoms and to control their allergies with the treatment recommended by their doctors. Drinking plenty of fluids and keeping the air in the house moist by using a vaporizer can help thin mucus and prevent its buildup in the sinuses. Limiting alcohol consumption also may help, because alcohol can cause nasal membranes to swell.
See also
Common Cold
Influenza
Meningitis
Osteomyelitis
Streptococcal Infections
Resources
Organization
National Institute of Allergy and Infectious Diseases (NIAID), Building 31, Room 7A-50, 31 Center Drive MSC 2520, Bethesda, MD 20892. The NIAID, part of the National Institutes of Health, publishes pamphlets and a fact sheet about sinusitis at its website, along with links to other websites offering more information.
Sinusitis
Sinusitis
Definition
Sinusitis refers to an inflammation of the sinuses, airspaces within the bones of the face. Sinusitis is most often due to an infection within these spaces.
Description
The sinuses are paired air pockets located within the bones of the face. They are:
- the frontal sinuses; located above the eyes, in the center region of each eyebrow
- the maxillary sinuses; located within the cheekbones, just to either side of the nose
- the ethmoid sinuses; located between the eyes, just behind the bridge of the nose.
- the sphenoid sinuses; Located just behind the ethmoid sinuses, and behind the eyes.
The sinuses are connected with the nose. They are lined with the same kind of skin found elsewhere within the respiratory tract. This skin has tiny little hairs projecting from it, called cilia. The cilia beat constantly, to help move the mucus produced in the sinuses into the respiratory tract. The beating cilia sweeping the mucus along the respiratory tract helps to clear the respiratory tract of any debris, or any organisms which may be present. When the lining of the sinuses is at all swollen, the swelling interferes with the normal flow of mucus. Trapped mucus can then fill the sinuses, causing an uncomfortable sensation of pressure and providing an excellent environment for the growth of infection-causing bacteria.
Causes and symptoms
Sinusitis is almost always due to an infection, although swelling from allergies can mimic the symptoms of pressure, pain, and congestion; and allergies can set the stage for a bacterial infection. Bacteria are the most common cause of sinus infection. Streptococcus pneumoniae causes about 33% of all cases, while Haemophilus influenzae causes about 25% of all cases. Sinusitis in children may be caused by Moraxella catarrhalis (20%). In people with weakened immune systems (including patients with diabetes; acquired immunodeficiency syndrome or AIDS; and patients who are taking medications which lower their immune resistance, such as cancer and transplant patients), sinusitis may be caused by fungi such as Aspergillus, Candida, or Mucorales.
Acute sinusitis usually follows some type of upper respiratory tract infection or cold. Instead of ending, the cold seems to linger on, with constant or even worsening congestion. Drainage from the nose often changes from a clear color to a thicker, yellowish-green. There may be fever. Headache and pain over the affected sinuses may occur, as well as a feeling of pressure which may worsen when the patient bends over. There may be pain in the jaw or teeth. Some children, in particular, get upset stomachs from the infected drainage going down the back of their throats, and being swallowed into their stomachs. Some patients develop a cough.
Chronic sinusitis occurs when the problem has existed for at least three months. There is rarely a fever with chronic sinusitis. Sinus pain and pressure is frequent, as is nasal congestion. Because of the nature of the swelling in the sinuses, they may not be able to drain out the nose. Drainage, therefore, drips constantly down the back of the throat, resulting in a continuously sore throat and bad breath.
Diagnosis
Diagnosis is sometimes tricky, because the symptoms so often resemble those of an uncomplicated cold. However, sinusitis should be strongly suspected when a cold lingers beyond about a week's time.
Medical practitioners have differing levels of trust of certain basic examinations commonly conducted in the office. For example, tapping over the sinuses may cause pain in patients with sinusitis, but it may not. A procedure called "sinus transillumination" may, or may not, also be helpful. Using a flashlight pressed up against the skin of the cheek, the practitioner will look in the patient's open mouth. When the sinuses are full of air (under normal conditions), the light will project through the sinus, and will be visible on the roof of the mouth as a lit-up, reddened area. When the sinuses are full of mucus, the light will be stopped. While this simple test can be helpful, it is certainly not a perfect way to diagnose or rule out the diagnosis of sinusitis.
X-ray pictures and CT scans of the sinuses are helpful for both acute and chronic sinusitis. People with chronic sinusitis should also be checked for allergies; and they may need a procedure with a scope to see if any kind of anatomic obstruction is causing their illness. For example, the septum (the cartilage which separates the two nasal cavities from each other) may be slightly displaced, called a deviated septum. This can result in chronic obstruction, setting the person up for the development of an infection.
Treatment
Antibiotic medications are used to treat acute sinusitis. Suitable antibiotics include sulfa drugs, amoxicillin, and a variety of cephalosporins. These medications are usually given for about two weeks, but may be given for even longer periods of time. Decongestants, or the short-term use of decongestant nose sprays, can be useful. Acetaminophen and ibuprofen can decrease the pain and headache associated with sinusitis. Also, running a humidifier can prevent mucus within the nasal passages from drying out uncomfortably, and can help soothe any accompanying sore throat or cough.
Chronic sinusitis is often treated initially with antibiotics. Steroid nasal sprays may be used to decrease swelling in the nasal passages. If an anatomic reason is found for chronic sinusitis, it may need to be corrected with surgery. If a surgical procedure is necessary, samples are usually taken at the same time to allow identification of any organisms present which may be causing infection.
Fungal sinusitis will require surgery to clean out the sinuses. Then, a relatively long course of a very strong antifungal medication called amphotericin B is given through a needle in the vein (intravenously).
Alternative treatment
Chronic sinusitis is often associated with food allergies. An elimination/challenge diet is recommended to identify and eliminate allergenic foods. Irrigating the sinuses with a salt water solution is often recommended for sinusitis and allergies, in order to clear the nasal passages of mucus. Another solution for nasal lavage (washing) utilizes powdered goldenseal (Hydrastis canadensis ). Other herbal treatments, taken internally, include a mixture made of eyebright (Euphrasia officinalis ), goldenseal, yarrow (Achillea millefolium ), horseradish, and ephedra (Ephedra sinica ), or, when infection is present, a mixture made of echinacea (Echinacea spp.), wild indigo, and poke root (Phytolacca decandra-Americana ).
Homeopathic practitioners find a number of remedies useful for treating sinusitis. Among those they recommend are: Arsenicum album, Kalium bichromium, Nux vomica, Mercurius iodatus, and Silica.
Acupuncture has been used to treat sinusitis, as have a variety of dietary supplements, including vitamins A, C, and E, and the mineral zinc. Contrast hydrotherapy (hot and cold compresses, alternating 3 minutes hot, 30 seconds cold, repeated 3 times always ending with cold) applied directly over the sinuses can relieve pressure and enhance healing. A direct inhalation of essential oils (2 drops of oil to 2 cups of water) using thyme, rosemary, and lavender can help open the sinuses and kill bacteria that cause infection.
Prognosis
Prognosis for sinus infections is usually excellent, although some individuals may find that they are particularly prone to contracting such infections after a cold. Fungal sinusitis, however, has a relatively high death rate.
Prevention
Prevention involves the usual standards of good hygiene to cut down on the number of colds an individual catches. Avoiding exposure to cigarette smoke, identifying and treating allergies, and avoiding deep dives in swimming pools may help prevent sinus infections. During the winter, it is a good idea to use a humidifier. Dry nasal passages may crack, allowing bacteria to enter. When allergies are diagnosed, a number of nasal sprays are available to try to prevent inflammation within the nasal passageways, thus allowing the normal flow of mucus.
Resources
ORGANIZATIONS
American Academy of Otolaryngology-Head and Neck Surgery, Inc. One Prince St., Alexandria VA 22314-3357. (703) 836-4444. 〈http://www.entnet.org〉.
KEY TERMS
Cilia— Tiny, hair-like projections from a cell. Within the respiratory tract, the cilia act to move mucus along, in an effort to continually flush out and clean the respiratory tract.
Sinus— An air-filled cavity.