This is the second part of Dr Eric cobb’s article in ‘PT on the net” from February 12th
Meet the Vestibular System.
(…)It is imperative to have a working knowledge of the human vestibular system because it plays a key role in the spinal movement symphony (Herdman & Clendaniel, 2014).
Also known as your inner ear, the human vestibular system is one of the most brilliant bio-engineering marvels on the planet. It also happens to be one of the “oldest” portions of human anatomy and its pathways, because they are related to stabilizing our vision and body and orienting us against gravity, are among the first to undergo myelinization while we are still in utero (Tecklin, 2007). What does all of that mean? It means it’s a really, really important system!
How Does It Work?
The vestibular system has two primary “divisions:”
- The Semicircular Canals
- The Otolith Organs (Utricle and Saccule)
Working together, these two divisions comprise 5 different receptors on each side of your head that work conjointly to keep you upright and moving through the world efficiently and safely.
- The semicircular canals are oriented at 90 degrees to one another (think X, Y, Z axes) and they are designed to respond to ALL head and neck movements. They are also in charge of an INCREDIBLY important reflex called the Vestibulo-Ocular Reflex.
- The otolith organs are designed to respond to linear accelerations in all planes of movement. The utricle senses horizontal linear movement (think railroad tracks) while the saccule senses vertical movements (think elevator).
The Spinal Complaint Connection
When you delve into the neurology of the vestibular system you are quickly going to encounter two different pathways from the inner ear into the body. These pathways are called the lateral and medial vestibulospinal tracts. Let’s take a quick look at their functions:
Lateral Vestibulospinal Tract – This tract projects ipsilaterally down the spinal cord (e.g., the right inner ear projects down the right side of the body) and helps maintain balance and posture by stimulating EXTENSOR MUSCLES of the spine and lower extremity (Fitzgerald, Gruener & Mtui, 2012). (…)
Medial Vestibulospinal Tract – This tract is found only in the cervical spine and above. It projects bilaterally down the spinal cord and is particularly involved in controlling the neurons associated with the spinal accessory nerves (Cranial Nerve XI),which innervate the trapezius and sternocleidomastoid muscles. These muscles are prime movers and stabilizers of the head and neck in flexion, extension, lateral flexion and rotation. As a result they are intrinsically related to both neck stability and mobility. And, if you spend any time evaluating necks and shoulders for a living, you know that they are OFTEN dysfunctional and overly tense. Additionally, this tract also projects upward and helps keep the eyes “yoked” together during rapid head movement, so you can keep your eyes on a target even as you move. This makes the medial vestibulospinal tract intimately tied to both head- and whole-body orientation and posture (Fitzgerald, Gruener & Mtui, 2012).
Are you starting to get a sense that this system might be implicated in some spinal issues?
Imagine this scenario: You are a young, active, mid-30’s office worker who likes to workout and play basketball on the weekend. During a game, your legs are cut out from under you and you take a hard fall, landing on your shoulder and banging your head a bit. Soon after, you begin to experience chronic neck and upper back tension and pain that interfere with your workouts and results in headaches when you spend a long day working on the computer. You see different professionals that provide temporary relief via a wide range of modalities but you never seem to fully heal… because the potential underlying cause of this neck and back tension hasn’t yet been addressed.
If this sounds like a familiar story, you may be hearing a desperate plea from your body and nervous system for a vestibular assessment!
Once you begin really looking at the massive impact of the vestibular system on movement, it becomes a virtual certainty that you are going to want to include some base level assessments and drills into your work with clients, as well as know how and when to make an appropriate referral. Because this is such a complex topic, please refer to the video that coincides with this article for examples of starting points that you can use with your clients. Stay tuned for Part 2 of the video…
For now, let me STRONGLY encourage you to begin an educational process for yourself around the complexities of the vestibular system. Both research and experience have shown that vestibular deficits often co-exist and are potentially causative in a wide variety of issues that seem far removed, including:
- Chronic Spinal Pain & Movement Disturbances
- Scoliotic Changes to the Spine
- Fatigue and Low Energy Levels
- Decreased Strength and Coordination
- Poor Flexibility
- Visual Disturbances
- Declining Sports Performance
- Anxiety Issues
As I have mentioned in a previous article, (http://www.ptonthenet.com/articles/the-six-muscles-to-include-in-every-training-session-3916#comments-container), in the emerging neuroscience of exercise and movement – understanding the neural contributors to movement efficiency is key, and this is especially important when we are dealing with the spine. The vestibular system is one of the primary players in this process and deserves special attention and training as a result
Finding a trainer that can add basic vestibular assessments and training to your workout session is obviously precious.
American Academy of Pain Medicine Facts and Figures on Pain. (2014). Retrieved from http://www.painmed.org/patientcenter/facts_on_pain.aspx#refer Fitzgerald, M.J., Gruener, G & Mtui, E. (2012). Clinical neuroanatomy and neuroscience (6th ed.). Elsevier Limited.
Herdman, S.J., & Clendaniel, R. (2014). Vestibular rehabilitation (4th ed.). F.A. Davis Company.
Tecklin, JS. (2014). Pediatric physical therapy (5th ed.). Baltimore, MD: Lippincott Williams & Wilkins.