The
Anatomy of a Sinus: How the Sinuses Work
Sinuses are air pockets
in the bones behind the face and jaw. There are four such chambers.
The first two exist at or shortly after birth:
- Maxillary sinus - behind
the cheeks
- Ethmoid sinus - between
the eyes behind the bridge of the nose
The other two develop later:
- Frontal sinus - Developed
around the age of seven, these are located in the area of the
forehead, over the brow.
- Sphenoid sinus - Developed
during adolescence, located behind the ethmoids and eyes, deep
in the face.
The sinuses, which make the mucus
that is intended to clean out trapped particles and bacteria, all
lead to the nasal passages. They are linked by a mucous membrane.
When the mucus is thin (under healthy circumstances), it is swept
out by miniscule hairs along the sinuses called “cilia”,
and draws bacteria and fungus out of the body through the nose.
Why do sinuses
get infected?
When the sinus passages become
narrow, swollen and/or constricted, the mucus collects, thickens,
becomes very attractive to bacteria and fungus lurking in the environment,
the flow doesn’t happen properly, and the problem mounts up.
Many things can contribute to
the narrowing of the sinuses:
- Consistent exposure to smoky, chemical and
toxic environments, or even short-term exposure depending on
the circumstances. A good example is working with harsh cleaning
products in a room with no circulating air.
- Stuffy noses from cold and flu
- Allergic reactions - see our Sinusitis vs.
Rhinitis page (Link)
- Over-use of or dependency on decongestant
sinus sprays.
- Chronic medical conditions which require
long-term medications.
- Long-term water sports involvement, especially
in chlorinated pools
- Anatomical irregularities, broken bones or
crushed cartilage in the nose, or previous rhinoplasty (nose
reconstruction).
Some of these in turn can result
in polyps forming in the nasal passages or sinuses. These are generally
soft non-cancerous growths, but nevertheless bothersome.
Bad sinuses can also affect
the ear tunnels, especially in children.
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