The superhero who controls your tongue: Let's learn about the Hypoglossal Nerve.

Today we're going to talk about a very important nerve in our body, but one that we sometimes don't pay much attention to. That nerve is the hypoglossal nerve , which controls the movements of our tongue. This little nerve does more than you might think. Let's see what it is.

What is the hypoglossal nerve?

Simply put, your hypoglossal nerve is like a special messenger that runs from your brain to your tongue . To be precise, it's one of the 12 pairs of cranial nerves in your head. Yes, there are 12 main pairs of nerves that are connected to different parts of your head. It starts at the base of your brain, called the brainstem. It then travels down your neck, branches out, and connects to the underside of your tongue and the base of your tongue.

The name "hypoglossal" comes from two Greek words: "hypo" meaning "under" and "glossal" meaning "tongue." So, the name itself tells you where this is located, right?

This is a motor nerve . That is, it carries messages from the brain to the muscles and makes them move. It's like an electric wire, but it doesn't carry electricity, it carries nerve impulses.

What are other names for this nerve?

It is called by several other names. Your doctor may also use these names:

• Cranial nerve 12
• 12th cranial nerve
• `(CNXII)` (This is an abbreviation used by doctors)

What is the function of the hypoglossal nerve?

Just imagine how much your tongue moves when you talk, swallow food, or make various sounds with your mouth! The hypoglossal nerve helps control all of those movements .

This nerve is mainly responsible for allowing us to do the following things:

• Make different sounds with your mouth (for example, a "click" sound made with your tongue).
• Move the things inside the mouth, that is, food and drink.
• Talk (our tongue bends into so many shapes when we talk, doesn't it?).
• Swallow the food (the tongue helps a lot in moving the food down the throat).

Imagine how difficult it would be for us to talk and eat if this nerve didn't work properly!

What muscles does the hypoglossal nerve control?

Your tongue is not just one muscle. It has many different muscles inside and connected to it. The hypoglossal nerve controls these muscles:

• Genioglossus muscles : These are the muscles that push your tongue forward. These muscles work when you stick your tongue out.
• Hyoglossus muscles : These pull your tongue back and flatten it.
• Intrinsic muscles : These are the muscles that change the shape of the tongue. For example, things like curling and narrowing the tongue.
• Styloglossus muscles : These move your tongue up and down.

It is because all of these muscles work together, in coordination, that we are able to make such complex movements with our tongue.

What is the location (structure) of the hypoglossal nerve?

As we mentioned earlier, this nerve starts at the base of the brain, near the brainstem , right above your spinal cord.

Before reaching the tongue, this nerve travels like this:

• It first travels down your spinal cord and connects to a complex network of nerves called the cervical plexus . This network of nerves controls the sensations and movements of your neck and trunk.
• It then travels down your neck, passing several important blood vessels (such as the Carotid Artery and the Jugular Vein) .
• It goes from the back of your throat to the bottom of your mouth, that is, the floor of the mouth.
• Finally, there, the branches branch off and connect to the muscles that control various movements of the tongue.

Can you imagine how complex a journey this little nerve takes?

What are the conditions that affect the function of the hypoglossal nerve?

Unfortunately, certain diseases and conditions can interfere with the function of the hypoglossal nerve, which can lead to the inability to properly perform the tongue functions we discussed earlier.

Here are some such situations:

• Amyotrophic Lateral Sclerosis (ALS) : Also known as Lou Gehrig's disease, this is a neuromuscular disease. The muscles gradually weaken. As the disease progresses, the hypoglossal nerve may not be able to communicate properly with the brain.
• Encephalitis : Encephalitis is a condition in which the brain swells, either due to a brain infection or a malfunction in the immune system. When the brain swells, the brainstem can become inflamed and put pressure on the hypoglossal nerve.
• Head and Neck Cancer : This refers to cancers that develop in the mouth, throat, or other parts of the head and neck. This nerve can be damaged either by the cancer itself or by cancer treatments (e.g., surgery, radiation therapy).
• Sleep Apnea : This is a sleep-related disorder. Breathing stops for a short time while you are sleeping. The hypoglossal nerve controls the muscles at the back of the throat. If these muscles relax too much while you are sleeping, the tongue can fall back and block the airway.
• Stroke : A stroke is a condition in which blood flow to a part of the brain is interrupted. This can be caused by bleeding inside the brain or by a blocked blood vessel. If the brain does not get enough blood, the communication between the hypoglossal nerve and the brain can be disrupted.
• Trauma : This nerve can be damaged by various accidents, such as car accidents, falls, and violent incidents. In some severe accidents, this nerve can even be severed.

Symptoms of Hypoglossal Nerve Damage

If your hypoglossal nerve is damaged, it usually only affects one side of your tongue . The tongue on the affected side becomes weak. Over time, the muscles on that side of the tongue can atrophy, and eventually the tongue can become paralyzed.

This may cause you to experience the following difficulties:

• Difficulty swallowing food (dysphagia)
• Difficulty swallowing food
• Difficulty speaking (dysarthria)

When nerve damage occurs due to ALS, the surface of the tongue may show subtle, twitching movements (fasciculations). These are like tiny twitches occurring within the muscle.

Important: If you experience sudden, severe pain in your neck or head along with these symptoms, it could be a case of a dissected internal carotid artery. If this happens, you should seek medical attention immediately.

How is the function of the hypoglossal nerve tested?

If your doctor suspects hypoglossal nerve dysfunction, they will first perform a simple test.

• You will be told to stick your tongue out straight . If there is nerve damage, the tongue will be pulled out on the side that is damaged.
• Also, you will be told to press your tongue against the inside of your cheek . Then the doctor will place his hand on the other side of your cheek and see how much pressure is coming from your tongue.

In addition to these basic tests, other tests may be ordered to find the cause:

• MRI scan (Magnetic Resonance Imaging - MRI) : This checks for signs of a stroke or something like a brain tumor.
• Spinal Tap / Lumbar Puncture : This can check for signs of cancer or infection.

Common Treatments for Hypoglossal Nerve Damage

Treatment for hypoglossal nerve damage depends on the cause of the damage . Your doctor will discuss this with you and determine the best treatment.

For example:

• For ALS, medications and various therapies are provided to control symptoms and slow the progression of the disease.
• Head and neck cancer can be treated with surgery, radiation therapy, and/or chemotherapy.

How can I protect my hypoglossal nerve?

Problems with the hypoglossal nerve can affect your ability to eat, speak, and swallow. Some causes, such as trauma and complications from surgery, are difficult to prevent. However, if you need surgery on your mouth or throat, choosing an experienced surgeon can help reduce your risk.

Also, taking care of your overall health can help prevent hypoglossal nerve dysfunction. These things can help:

• If you have a chronic disease like ALS, follow your doctor's instructions carefully to manage your disease .
• Stroke can be prevented by adopting a healthy lifestyle (e.g., eating a balanced diet, exercising, and controlling blood pressure).
• Maintain a healthy weight . This can help prevent sleep apnea from developing or worsening if you have it.
• If you use tobacco, quit smoking and limit your alcohol intake. Both of these can help prevent head and neck cancers.

When should you see a doctor about hypoglossal nerve problems?

If you experience any of these symptoms on one or both sides of your tongue, see a doctor immediately:

• Difficulty speaking (aphasia or dysarthria) or difficulty swallowing (dysphagia).
• A state of unconsciousness (like numbness of the tongue).
• Muscle weakness (like not being able to control the tongue properly).
• A feeling of pain or burning .
• An inability to coordinate movements (like tongue-tied).

Take-Home Message

We don't usually think much about the hypoglossal nerve, but it's a very important part of our body. It helps us move our tongue, talk, swallow, and move things around in our mouths. Conditions like stroke, cancer, and ALS can affect the function of this nerve. Living a healthy lifestyle can help protect your hypoglossal nerve from some of these conditions. If you experience any unusual symptoms related to your tongue, be sure to talk to a doctor. It's the smart thing to do!

` Hypoglossal nerve, lingual nerve, cranial nerves, tongue control, speech difficulty, swallowing difficulty, neurological diseases