Ethmoid Sinus

What is the ethmoid sinus?

Your ethmoid sinuses are one of four paired cavities in your face called your paranasal sinuses. Your paranasal sinuses include your frontal sinuses, ethmoid sinuses, sphenoid sinuses and maxillary sinuses. Together, they’re part of a drainage system that allows mucus to carry germs and allergens out of your nose.

Like your other paranasal sinuses, your ethmoid sinuses drain into your nasal cavity. They’re between your eyes, behind the bridge of your nose.

What does the ethmoid sinus do?

Your ethmoid sinuses are part of the network that filters the air you breathe. They also make mucus that keeps the tissue lining your nose moist and healthy. Harmful substances (like dust and germs) that enter your nose get stuck in the mucus that drains out of your nose. Most of us think of mucus as nasty. But it’s actually a sign that your sinuses are helping flush out material that can make you sick.

Your ethmoid sinus likely plays other roles, too.

For example, as these sinuses are hollow, they reduce the weight of your skull. They may help absorb some of the impact during head injuries, protecting your brain. And your ethmoid sinuses may help give your voice resonance — a warm, layered sound — that it may not otherwise have.

Where are the ethmoid sinuses located?

Your ethmoid sinuses are inside your ethmoid bone. This spongy, cube-shaped bone separates your nasal cavity from your brain and eye sockets.

Imagine having X-ray vision. If you were facing a mirror, you’d see your ethmoid sinuses behind the bridge of your nose in between your eyes. One ethmoid sinus would be on the left side of your nose bridge. The other would be on the right.

But you wouldn’t see two empty air-filled cavities. This is because each ethmoid sinus contains several tiny cavities, or “pockets,” called air cells. Adults have anywhere from three to 18 of them on each side. Together, the air cells in your ethmoid sinuses can hold between 2 to 3 milliliters (around 1/2 teaspoon) of air.

What is its structure?

Your ethmoid sinuses can be divided into two parts. The divisions reflect the different pathways mucus uses to drain from your ethmoid cells into your nasal cavity. All the various pathways together are called the ostiomeatal complex.

• Anterior ethmoid sinuses. Some of these ethmoid air cells drain through a passage called the hiatus semilunaris. Your frontal and maxillary sinuses also drain through this passage. Others drain through a structure called the ethmoidal bulla.
• Posterior ethmoid sinuses. These cells drain into the sphenoethmoidal recess. It sits inside a structure called the superior meatus. Your sphenoid sinuses (found deeper in your skull) also drain here.

The anatomy is complex. What’s important to remember is that your ethmoid sinuses drain through certain pathways. In some cases, they share pathways with your other sinuses. These paths keep mucus flowing out. They keep air flowing in and out when you breathe through your nose.

What are the common conditions and disorders that affect this body part?

Colds, allergies and ethmoid sinus inflammation (ethmoid sinusitis) are the most common conditions that cause issues. This inflammation can sometimes lead to infections. The shared pathways that allow your sinuses to keep air flowing and mucus draining are narrow. This means that swelling from inflammation can trap germs and cause pesky symptoms.

Usually, these conditions don’t cause serious issues and clear up on their own eventually.

Benign, precancerous and cancerous tumors can also form in your ethmoid sinuses. But this is rare.

Signs/symptoms something isn’t working right

Symptoms of inflammation affecting your ethmoid sinuses include:

• Eye pain or swelling around your eye
• Headaches
• Loss of smell (anosmia)
• Pain or pressure in the bridge of your nose
• Runny nose
• Stuffy nose

Double-vision (diplopia) unrelated to an injury may be a sign of a tumor in your ethmoid sinus.

How can I stay healthy?

The best way to care for your ethmoid sinuses is to avoid allergens and take steps to keep from getting sick. This includes regularly washing your hands, getting plenty of sleep and eating nutritious foods.

If you’re experiencing symptoms of inflammation in your ethmoid sinus, there are things you can do at home to feel relief, like:

• Doing nasal irrigation to clean or unclog your ethmoid sinuses
• Using a humidifier to moisten and soothe the irritated tissue
• Taking over-the-counter NSAIDs to calm the inflammation
• Using nasal steroid sprays such as fluticasone to calm the inflammation

Schedule an appointment with a healthcare provider if your symptoms get worse or don’t improve after two weeks.