Why did I get dizzy after I hurt my neck?

Neck injuries come in all shapes and sizes.

Okay maybe not the best way to say that. Necks come in all shapes and sizes. Injuries are also very unique based on the individual and what happened to cause the injury and all the things that happened before the injury.

Often times individuals that injure their neck get dizzy afterwards. Sometimes that dizziness stays around and sometimes it seems to go away on its own.

Dizziness isn’t the only seemingly odd symptom that shows up with neck injuries but it is a common one and one that luckily due to some amazing scientist and researchers we know a little more know about than we did in the past when it comes to dizziness.

Let’s get started.

The opposite of feeling dizzy is feeling balanced. When it comes to the human body we have a lot going on in order to keep us balanced and it’s as good of a place to start as any when it comes to discussing dizziness.

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From Chapter 4, Handbook of Clinical Neurology

When it comes to keeping the body upright and balanced there is a lot going on behind the scenes.

If you look at the figure on the right, the brain gets information(input) and processes the information from multiple different sensory systems in the body in order to keep us balanced.

These systems are our eyes (visual system), inner ear (vestibular system) and structural system (somatosensory system). The brain receives information from these three systems and then combines, organizes, and interprets the information. 

These systems all work together very well and due to them working together really well they’ve developed reflexes that keep us upright and balanced. 

Reflexes are an action that is performed as a response to a stimulus without us having to think about it. When it comes to the body these reflexes are really important because there is a ton of information being processed at one time and it would be impossible to consciously think about all the information that is coming in and leaving.

Let’s get back to reflexes. 

Three of the reflexes that help keep us balanced are the; vestibulospinal reflex, vestibulo-occular reflex, and the cervico-occular reflex. 

These three reflexes, as I’ve said multiple times, work together to keep us balanced. 

The vestibulospinal reflex contributes to the process of us staying upright in two main ways. 

First the vestibular system, our inner ear, sends information about the position of our head as it relates to vertical. It’s able to do this due to some amazing “ear-gineering”.

Ok, seriously the inner ear is really cool. There are three “hollow” tubes that have little hair cells that line the tubes. There is also a fluid that that hangs out with these hair cells. When we turn our head, tilt our head, move our head and neck, in any way that fluid rushes over the hair cells and then based on how, when and where these hair cells are affected the brain knows how our head is oriented compared to vertical.

The vestibulospinal reflex is the reflexive response of muscles of the spine and neck to keep us upright. Our vestibular system (inner ear) tells the brain this information so that certain muscles relax and contract in a coordinated and reflexive nature to keep us upright. 

McCall, A. A., Miller, D. M., & Yates, B. J. (2017). Descending influences on Vestibulospinal and Vestibulosympathetic Reflexes. Frontiers in Neurology, 8. https://doi.org/10.3389/fneur.2017.00112 

A fun way to feel the vestibulospinal reflex in action is to put your hand on your lower back feeling the muscles of your back and then bring you head forward like you’re looking at the ground, look all the way up, then bring your left ear close to your left shoulder and your right ear closer to your right shoulder. When you do this you should feel the muscles of the lower back contracting and relaxing.

Next is the vestibulo-occular reflex (VOR).

This reflex works similar to the vestibulospinal reflex. However as opposed to muscles of the spine and neck responding, the VOR results in stabilizing our eyes as we move our head. For example say a bird flies by and you turn your head quickly to follow the birds flight through the air. The fluid in the inner ear is going to flow over the hairs telling the brain the head and neck is moving in a specific way. The ocular aspect of the vestibular-occular reflex is small movements of the eyes caused by reflexive contraction of little eyes muscles that we don’t perceive while we move our head. These movements of the eyes are what stabilize our vision as we move our head and neck. Without the VOR it would be nearly impossible to walk down the street and still be able to read signs or even recognize people.

Last and definitely not least is the cervico-occular reflex (COR). The COR is a reflex that works similar to the others but it’s also quite different.

The previous reflexes were a response/reflex based on the position of the head from information relayed from the inner ear (vestibular system). However, with the cervical-occular reflex the information about the position of the head and neck is picked up by sensors in the muscles of the head and neck. These sensors are called proprioceptive afferents. We talked about afferent and efferent communication in the body in a past blog and you can read about it here.

Basically afferent information is coming from the body to the brain and efferent information is information from the brain to the body that is causing a response in the body.

These proprioceptive sensors in the neck work by sending information about the movement of the muscles of the neck and allows the eyes to respond and stabilize as we turn our head. Want to know where the majority of these sensors are located?

Right at the top of the neck. Think head tilt might negatively affect those sensors? 

The combination of these three reflexes and others allow us to move and function without getting dizzy because these reflexes work to stabilize the eyes as we move. Essentially special sensors are able to tell us our position and then the eyes muscles are able to react accordingly to stabilize the eyes and keep us balanced. 

So what happens when we injure our neck and why does that lead to dizziness with some individuals?

A lot.

First.

Fatigue. Fatigue is extreme tiredness. In the case of whiplash from a car accident, when hit from behind the head and neck is initially pushed(extended) into the back of the seat and head rest (if properly adjusted) then flexed forward rapidly resulting in a whiplash injury.

While this is occurring a couple other things happen as well. The muscles of the neck try to stabilize and hold the head and neck in a stable position and at the same time many of these muscles are pulled or strained through their maximal length.

Remember those special receptors and sensors in the neck that are really important to keep us balanced?

Well the quick flexion and extension movement of the entire neck in a rapid fashion while the muscles are also trying to contract and maintain stability, injures those receptors in the neck, and injures the muscles. 

This then results in inaccurate information being sent to the brain from the injured receptors/sensors and inability of the muscles to properly contract and relax. 

This inaccurate information being sent to the brain when combined with the information from the vestibular system results in sensory mismatch between the sensors coming from the neck and the sensors coming from the vestibular system. 

The result?

Dizziness, feeling unbalanced, and feeling unstable in up to 50% of individuals that have a neck injury.

Luckily those sensors and muscles can heal and that’s one of the things we help facilitate here at Optimize Chiropractic by utilizing a Data-Driven approach.

References

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