Migraine Gets on My Nerves
Have you heard of the trigeminal nerve? It’s also called the 5th cranial nerve and is responsible for motor control, touch sensation, and pain perception throughout the eyes, face, cheeks, jaw, and head. It is the largest of all cranial nerves. While not the ultimate cause of the pain involved in migraine, it certainly has a big part to play.
Functional problems with the trigeminal nerve are not the cause of migraine. Migraine actually begins deep inside the brain. Abnormal functioning of the trigeminal nerve occurs both during the acute phase and between attacks. These changes are not affected by disease duration or attack frequency. Taking abortive medication does not correct the problem either. Disruptions in the functioning of the trigeminal nerve occur on both sides of the head, even when pain is only felt on one side. This discovery led researchers to conclude that the problem actually starts in the brainstem. The problem lies with the way the brain perceives and interprets stimuli.
Most of us know that we are extra-sensitive to stimuli. The good news is that there is scientific evidence to prove we are not imagining it. Our trigeminal nerve over-reacts because of some yet-undiscovered problem deep inside our brainstem. Now let’s look at exactly what areas are affected by this trigeminal nerve.
The trigeminal nerve starts in the brainstem, forming a single nerve root on either side of the brain. That nerve root then branches out across the front of the head and face, providing sensation to the top of the head, forehead, eyes, nose, cheeks, mouth, teeth, and jaw. It is the largest cranial nerve and takes up a lot of real estate on our heads. From each nerve root, three main branches spread across each side of the face and head: ophthalmic, maxillary, and mandibular nerves.
This is the uppermost branch that spreads across the scalp and forehead. It is responsible for sensation and pain perception in these areas:
- Frontal sinus
- Ethmoidal sinus
- Upper eyelid
- Bridge and tip of nose
In addition to sensory input, it is also responsible for the lacrimal gland that produces tears in the eyes.
The maxillary nerve spreads across the temple and face, down to the upper jaw. The sphenopalatine ganglion (SPG) is located just below the terminal ends of this nerve deep inside the maxillary sinuses. It is responsible for sensation and pain perception in these areas:
- Lower eyelid
- Maxillary sinus
- Nasal cavity
- Upper lip
- Upper jaw, plus teeth and gums
- Roof of mouth
The mandibular nerve spreads across the lower third of the face, lower jaw, and mouth. It even spreads across the temple and above the ear. It is responsible for sensation and pain perception in these areas:
- Scalp area above the ear (temple)
- External ear
- Lower lip
- Lower jaw, plus teeth and gums
- Anterior 2/3rd of tongue (not taste)
- Floor of mouth
Because the trigeminal nerve covers such a wide area of the face and head, it is easy to see how inflammation and irritation of this nerve can create such a wide variety of painful responses. No wonder our symptoms are so varied! One person will feel pain in and around the eye. Another will feel pain in the face and cheeks, similar to the pain of a sinus infection. Yet another will complain of phantom tooth pain. Sometimes the forehead, or temple, or even the ears hurt. The combinations appear limitless.
While other nerves that affect the rest of the head are also involved in pain perception, when it comes to migraine, the trigeminal nerve has a lot to answer for. Quite literally, migraine gets on my nerves.
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