What are sinuses?

Sinuses – also known as paranasal sinuses – are the small, empty spaces that sit behind your cheekbones and forehead, connecting to the inside of the nose to form a network with your nasal passages.

The exact function of sinuses isn’t fully understood, but it’s believed they may serve a few beneficial purposes. These include helping to control pressure in the skull, as well as keeping the air we breathe in via our nasal passages both moist and warm.

The sinuses naturally produce mucus that helps lubricate the inside of the nose. In normal circumstances, this should drain away freely through your nose and your throat.

However, when the tissue lining your sinuses swells – often caused by allergies and infections – it can prevent this natural drainage, which might lead to pain and a feeling of being bunged up.

Discover more about sinuses, how they work and the conditions that can affect them.

In this article:

  • Types of sinuses and where they’re located

  • Function of sinuses and how they work

  • Sinus conditions and how to treat them

Types of sinuses and where they’re located

Sinuses are split into four pairs, all located within the head. The structure of each of these sinus pairs is made up of a cavity on the right and left side of your face.

As their name suggests, they’re found around your nose and nasal cavity. Each different type of paranasal sinus is named after the bone it’s nearest.

Maxillary sinuses

The maxillary sinuses are the largest of your paranasal sinuses, typically measuring around one inch across. They have a pyramidal shape and sit on either side of your nose, beneath your cheekbones (maxillae) and above your teeth. These sinuses drain into the nose through a hole called the ostia.

Frontal sinuses

Frontal sinuses are located closer to the front of your skull than other types of sinuses, positioned on either side of the forehead (frontal bone), just above your eyes. They typically have a triangular shape, can vary in size and are the closest sinuses to the nasal passage.

Ethmoid sinuses

Unlike other types of sinuses, the ethmoid sinuses aren’t made up of singular sacs or cavities. Instead, there are usually several small sacs within the ethmoid bone that make up this sinus pair, which open onto the nasal passage. The ethmoid sinuses are usually extremely small at birth, but can grow to around the size of a walnut as you get older.

Sphenoid sinuses

Sphenoid sinuses sit the furthest back in your skull, between the upper part of your nose and the back of your eyes. They’re close to the optic nerve and pituitary gland. Sphenoid sinuses tend to grow along with your skull, reaching their full size after puberty.

SUDAFED® Sinus Symptoms

Which Sinuses Are Causing Your Pain

When suffering with a sinus condition, the location of the pain will normally indicate which of your sinuses is affected.

For example, if you feel pressure and pain in your cheeks, it may be the case that your maxillary sinuses are blocked or swollen. A headache that originates behind the eyes, on the other hand, may be a sign of issues with the sphenoid sinuses.

Function of sinuses and how they work

The true function of sinuses still isn't 100% clear. But there are many roles that doctors believe they may play, including helping to keep your nasal passages moist. The tissues of your sinuses produce mucus, which helps to lubricate both your sinuses and nasal passages.

The layer of mucus lining your sinuses is also believed to form part of your body’s immune defences, helping wash away any pollutants, dust, bacteria and other irritants that could lead to health problems.

Other functions it is believed the sinuses may carry out include:

  • Serving as resonating chambers for speech

  • Helping to lighten the weight of your skull

  • Protecting the face from trauma

  • Protecting the nose from rapid air temperature changes.

How do sinuses work?

Sinuses are part of a complex nasal network, made up of air flow and drainage passages. When you breathe in, the air will pass through your sinuses and into your nose.

The sinuses also produce mucus that drains into the nose to lubricate themselves and the nasal passage. Both air and mucus makes its way into the nose through small holes called ostia.

Tiny hairs called cilia help to move mucus through your sinuses – where it drains into the nose – before reaching your throat, where it is then naturally swallowed.

Sinus conditions and how to treat them

There are several common conditions that can affect your sinuses, causing them to swell or become blocked. If your sinuses do become blocked, it can prevent mucus from draining away, which can leave you feeling in pain and bunged up.

Some of the most common problems that could cause sinus pain include:


Sinusitis – also known as a sinus infection – is a term used to describe the swelling of your sinuses caused by an infection. It should clear up on its own within two to three weeks, but over-the-counter medication can help reduce your symptoms and leave you feeling more comfortable.

The symptoms of sinusitis can vary depending on which types of sinus are affected. Typically, however, symptoms will include:

  • Pain, swelling, pressure and tenderness around your cheeks, eyes or forehead

  • A blocked or stuffy nose

  • Reduced sense of smell (known as temporary anosmia)

  • Green or yellow mucus discharge from your nose

  • Headaches

  • Fever

  • Toothache or jaw pain.

Common cold or flu

The common cold and flu are caused by viruses passing from person to person through sneezing and coughing. Both conditions can cause headaches and sinus pain or pressure.

The common cold is also associated with a blocked or runny nose and can often lead to further sinus infections. This is because the cold can cause the sinuses to swell – trapping air, mucus and bacteria inside.

Allergic Rhinitis

Allergic rhinitis describes the inflammation of your nasal passages and sinuses caused by an allergen. These differ from person to person, but typical allergens include:

  • Pollen

  • Dust

  • Mould

  • Dander (flakes of skin from certain animals).

When you breathe in an allergen, it triggers an immune response, which causes your body to produce more mucus and the blood vessels in your nose to swell.

How to treat sinus conditions

Most sinus conditions will clear themselves naturally within a week or two, but there are some other ways to ease and soothe your symptoms, including:

  • Using over-the-counter pain relief, such as paracetamol or ibuprofen

  • Cleaning your nasal passages with a saltwater solution

  • Drinking plenty of fluids

  • Getting enough rest.

You can also treat most conditions by using over-the-counter medication like the SUDAFED® Sinus Pressure and Pain tablets that work to relieve pressure and pain and helps unblock your sinuses. They also help provide relief from the headache, fever and discomfort that often accompanies sinus congestion. SUDAFED® Sinus Ease Nasal Spray contains Xylometazoline and helps tackle sinus congestion, offering relief for up to 10hrs.

Our range of sinus pain products work to help ease sinus congestion and relieve the pain and pressure swollen sinuses can cause.

When to see a doctor

If your sinus condition has not cleared up within a week, you should contact your doctor, as it could be a sign of another illness.

You should also arrange to see a doctor if:

  • You suffer extreme congestion or pain

  • Painkillers and decongestants don't help to ease your symptoms

  • Your symptoms return repeatedly.

These could be a sign of nasal polyps or another chronic condition, which may require additional treatment from your GP.

How Does SUDAFED® Work: Active Ingredients

Active Ingredients

Learn more about our active ingredients

Help unblock your stuffy nose and breathe easier through your nose with SUDAFED®