vision – Essential Physical Therapy

It was a beautiful sunny day, not too hot with a nice cool breeze. As I jogged along the trail that passes through the meadow by my house, taking in the thousands of bright blue chicory flowers, I reflected on how lucky I am to live in such a beautiful place, to have a healthy body…. OUCH!

My knee was bugging me again, as it sometimes does when I’ve been running a lot without much cross training. Not that long ago I may have endured it, knowing that I would do some manual therapy or soft tissue work when I got home to try and coax my body back into a better alignment. Maybe I would have checked out my running form-making sure my core was engaged, and that my cadence was just right.

But today I know more. Thanks to the postural restoration institute, or PRI for short, I have such a deeper understanding of how so many things affect our movement and anatomy. I knew that the best thing I could do was just be more aware of the left side of the trail as it whizzed past. As I did that, my knee instantly felt much better.

Wait whaaaat??? Yup. Seriously. I simply became more aware of my left peripheral vision, which made my knee feel better.

Little disclaimer here…this is not to say that everyone who goes running will instantly be painfree by looking to the left, everyone has unique needs and nuances.

That said… it is a good idea to be aware of your peripheral vision when running and in general…more on that later.

But WHY??? Why would what I’m doing with my eyes affect my knee pain?

It’s all because of this special bone at the center of our head called the sphenoid.

Before we get into what this could possibly have to do with my knee, we should first ask ourselves…

Why Is the Sphenoid Bone So Special?

Here are just a few reasons…

The sphenoid bone attaches to our jaw, our eyes, and our ears.
The nerves that tell us to rest or digest or fight or flee or freeze pass through this bone.
The main arteries that supply blood flow to your brain pass through this bone.
The position of this bone determines the amount of pressure on your brainstem, which contains the apparatus to help your body organize movement.
The pituitary gland, which performs life-sustaining functions, nestles nicely into a tiny protective saddle in the sphenoid bone.

I could keep going, but I think you get the point. This bone is responsible for a lot of important stuff!

Even just a tiny tweak in the position of the sphenoid could cause all sorts of repurcussions, many of which seem completely unrelated.

What Might Tweak a Sphenoid’s Position?

The way your teeth touch matters big time to your sphenoid.
- The sphenoid interacts with your top and bottom teeth via muscles and nerve endings, but even the bony position of your jaw and maxilla (the bone that holds your top teeth) push against the sphenoid in certain ways. Not to mention, the periodontal ligament is HIGHLY sensitive to pressure and gives you lots of reference as to where you are in space. This neural information is then processed by your BRAINSTEM (remember that guy?) And what’s between your teeth and your brainstem? The sphenoid.
- Have you ever had dental work done and had the position of your tooth end up just a little higher or lower? If you have, you know it. Your body knows it. Everything feels off, you can’t relax until that tooth is back to where you like it! That’s the sensitivity of the periodontal ligament and the sphenoid position at play.
Head injuries and concussions.
- I don’t think I really need to explain why a blow to the head can affect sphenoid position and surrounding function. But what most people don’t realize is that you don’t have to hit your head to get a concussion. Whiplash, blast exposure, falls, all these things can result in jostling the contents of the skull.
How you use your eyes.
- Remember, the muscles that move your eyes around attach to your sphenoid. If you use your eyes the same way most of the time (like staring at a screen, for example), this can pull on the sphenoid.
The neck.
- The poor head is at the whim of what the neck is doing. And the neck is at the whim of what the body is doing underneath it! Think of a house that is built on clay. When first built, everything is nice and level. But then, after a big rainstorm, different parts of the clay expand at different rates due to the moisture, and the foundation starts to shift and become unlevel. Of course everything above the foundation will also become unlevel. Similarly, if your body is imbalanced below your sphenoid, you will likely also have imbalance above.

Of course there are other situations where certain visual or dental changes (surgical or otherwise) can affect how you hold your body below, because, unlike a house, the body’s roof (the cranium) has just as much of an effect of where the foundation (rest of the body) sits due to all the sensory input we get from our head telling us where we are in space.

Don’t believe me? try standing on one foot. Got it? Good. Now try doing that with your eyes closed. Little harder? That’s because you’re getting information about where you are relative to the ground from your eyes, not just your feet.

Also, I have to say that if you had a head injury or dental work or vision work, this does not doom you to a life of a crooked sphenoid! It can certainly have an effect, but in most people it is manageable with the right program of manual therapy and movement techniques.

So back to my knee. Why did being aware of my left visual field help my knee?

At a purely structural level, there is some effect of letting my eye position change to pull on my sphenoid in a different way.

On a deeper, subtler, neurological level, being aware of the left does several powerful things.

Firstly, it reminds my body to become centered instead of pulling to the right, which I do (and most people do) because of our anatomy and the way our brains are wired. This is especially important for me since I have had a head injury which included broken facial bones.

Secondly, it opens up my left peripheral vision, which creates a sense of expansiveness in my body, thus allowing the sphenoid and surrounding bones to spread and widen. This takes pressure off of all those neural and vascular structures, and lets my body relax out of a state of tension.

When our bodies are held in a tense and protective state, we can’t rotate well through our torso. A side to side alternating activity like running absolutely requires the ability to rotate. If you can’t rotate at your trunk, your body will do it somewhere else. For me, it was my knee.

As soon as I let my left visual field soften and open, my body got a signal (or many signals, rather) to reposition itself into a more optimal position, subconsciously. I could rotate better, breathe better, and didn’t need to put any extra torque on my knee.

Well, I know this is a pretty heady conversation (get it? Heady? Skull? Ok I know, too punny) but it is one worth having.

Because sometimes you do all the right things and still aren’t feeling better or where you want to be with your sport, your breathing, your health, or your ability to do the things you want to do.

When that’s happening, it’s time to look at what’s happening from the neck up to determine if something there could be inhibiting your progress.

Here’s a simple but powerful technique to try that will help with restoring sphenoid position.

Visual System

One of those systems is our vision. Have you ever been parked in your car and slammed on the brakes because the car next to you started to move? Nothing else changed except your visual perception, which made it appear you were moving. As a result, your body reacted. These reactions are constantly happening on a smaller, subconscious level as we negotiate our environment. Don’t believe me? Try balancing on one foot. Now, try that again, but close your eyes. Once we take away the visual input, balancing is much harder.

The visual system is one of the ways that we balance.

Somatosensory System

Another way we balance is with our somatosensory system. This system is the information we get from our body of where we are in space, primarily our feet. All of our joints have specialized nerves in them that tell our brain their position relative to a surface. There is a high density of these nerves in your ankles. To experience the somatosensory system in action, try again to balance on one foot. Notice how much harder your ankle is working, with little micro adjustments, to balance when you have only one foot on the floor instead of two. That’s because you’ve reduced your “somatosensory input” by reducing the amount of contact you have with the ground. Just like our vision, our somatosensory system is constantly sending signals to our brain and making micro adjustments based on where we are relative to a surface. This is happening whether we are standing, sitting, lying down, doing a handstand, walking or running.

We are able to balance with our somatosensory system, which uses our feet and ankles as reference centers to keep from falling over.

Vestibular System

The third system in our body that keeps us from falling over is our vestibular system. This system is usually the hardest to understand because we can’t see it, and we don’t notice that it is working. However, when it is not working, we really feel it.

The vestibular system is a small organ that lives deep to the ear, and you have one on each side. It is often referred to as the “inner ear” for its location, but you cannot get to it from your ear because it is separated by a membrane (the ear drum). It shares a nerve with the part of your body that manages hearing, called the cochlea.

The vestibular system or “inner ear,” shown above in blue, is located deep to the membrane of the ear drum.

The vestibular system consists of three semi-circular canals that are filled with fluid. When we move our head, this fluid is displaced. This displacement activates nerves within the vestibular organ and sends a signal to your brain with information about which direction your head is moving and how to adjust your eyes to account for this. This is a crucial function for daily activity. Think about walking. When we are walking, our head is constantly bobbing up and down with each step. However, we do not perceive this because of the vestibular system communicating with your eyes to account for this.

When Systems Fail

These three systems, visual, somatosensory, and vestibular, all have to work together. When they don’t, we can feel dizzy, off balance, or “not quite right.”

The system that is usually affected in feelings of dizziness is the vestibular system. A common cause of dizziness is called benign paroxysmal positional vertigo, or BPPV for short. This is when a small crystal of calcium-carbonate becomes displaced from another region of the vestibular organ and ends up in one of the fluid-filled, semicircular canals. Because the inertia of the crystal is greater than that of the fluid, the brain and eyes receive a signal that you head is still moving when actually it has stopped. Therefore, this type of dizziness usually occurs with head movements and creates a spinning sensation. It can be very uncomfortable, and is treated by a maneuver that positions the crystal back to its original location. Crystals can become dislodged during a head trauma. Also, as we age the crystals do not adhere as strongly to their original location and can come loose all on their own.

The vestibular system can also be damaged by a virus. Usually, someone who has this issue had a stomach virus or head cold up to two weeks before they started feeling dizzy. This person also gets dizzy with head movements due to the virus affecting the nerve that sends information from the semicircular canals to the brain, body and eyes.

Our sense of balance can be affected by an infection that makes its way to the nerve transmitting signals from the vestibular organ.

When our vestibular system is damaged or not functioning as well, we rely more heavily on other systems of balance, usually our vision. We usually don’t rely as much on our somatosensory system because in our day to day we are far more used to using our eyes to stabilize (computer work, driving, watching TV) than we are to using our somatosensory system (walking on uneven surfaces, balancing, crawling). This can make us feel dizzy when we are in an environment with lots of visual stimulus, or make us feel off balance or dizzy when we are in the dark or low light. After a while, we might notice that our neck becomes stiff, because we also avoid head movements that may make us feel dizzy.

Our bodies and brains are extremely good at compensating, but we can only compensate for so long. For individuals who have dizziness or imbalance and try to “just deal with it,” their problems often become worse as the compensations only grow stronger. This is because your body will always take the path of least resistance, which means it will always preferentially use the systems that are already strong (usually vision) and therefore the ones that are weak (vestibular and somatosensory) become weaker and weaker. This creates an imbalance that affects us negatively in many ways, because there are many moments in life we need all three systems to be working well and harmoniously.

So what to do if you suspect your balance systems are, well, out of balance? The best thing to do is to strengthen those that are weak. You can do this by performing balance activities with eyes closed, or incorporating head motion into your activities. This way you will stimulate the somatosensory and vestibular systems, and with eyes closed the visual system will not be able to take over.

Tag: vision

The Revolutionary Bone that No One Talks About