Have you ever wondered why eating ice cream or drinking a Slurpee gives you a headache? Or why shooting pain in your arm or jaw is a symptom of a heart attack? These are both examples of referred pain, when you feel pain in one part of your body (such as your mouth or heart) in another part of your body (such as your head or your arm). This strange phenomenon is actually very common, and understanding it can help you see the connection between some of the chronic pain you experience and its root cause.
Examples of Referred Pain
We listed a couple common examples of referred pain above, but there are many other common ones. Some others include:
Pharynx pain felt in the ear
Esophagus pain felt in the chest
Live pain felt in the right shoulder
Pain in the ovaries or spleen felt low in the left shoulder,
Lung pain felt in the left shoulder and neck
All of these referred pain examples can mask symptoms of serious health conditions.
Understanding the Cause of Referred Pain
There is no single accepted explanation of the cause of referred pain. However, many models share similar elements, and this explanation generally works and fits the information we have.
We often talk about the network of nerves in our body as a network of wires or fiber optic cables that carry information in our modern age. However, our nerves are made up of living cells in an organic network. A wire connects between two specific points and will only carry signals from the one point to the other. However, your nerves connect in many ways, and pass signals in multiple directions. It’s even possible for nearby nerves to get excited when one nerve is firing pain signals.
Your brain understands this, and the final part of you becoming aware of pain is when your brain makes a judgement call about where the pain is coming from. Usually, it’s accurate, but sometimes it’s not, which is when we experience referred pain.
Adjacent Nerves and Referred Pain
The most common cause of referred pain is that the two nerves involved, the one that is actually reporting the pain and the one your brain thinks is reporting the pain, are adjacent somehow. Often, they’re on the same branch nerve, such as the trigeminal nerve, which is supposed to report pain from your temple as well as your mouth, which is why you experience brain freeze in response to cold foods and drinks.
Or, they may enter the spinal column at the same point, such as the nerves from your left arm and those from your heart. This is also why you may experience shoulder pain from illnesses in your stomach, gallbladder, liver, and other internal organs.
Learned Referred Pain
Other times, you may experience referred pain between two regions that don’t have adjacent nerves. This most often happens after you suffer an injury, and your body learns to expect pain from the injured area. Long after your injury is healed, your brain may mistakenly refer new, unrelated pain to the injured area.
All referred pain is, to some extent, learned. For example, your brain refers stomach pain to the shoulder because it has learned that pain is more likely to be coming from the shoulder than the stomach.
Referred Pain and TMJ
TMJ is responsible for many potential pains. It can cause pain in your face, your head, your eyes, and your teeth, as well as jaw pain. That’s because all these areas report pain along the trigeminal nerve. TMJ can cause pain by either resulting in pain in your jaw, which may be referred elsewhere, or a displaced jaw or jaw muscles can irritate the trigeminal nerve, resulting in pain that comes from the nerve but is referred to any of the tissues the nerve reports from.