The Anatomy of Anterior Head Syndrome (AHS)
Anterior head syndrome (AHS), aka “forward head posture”, is a condition that many people world wide suffer from. For some people, there are no symptoms to indicate that their posture is less than perfect, however, in others, many other symptoms will present themselves as a result. Let’s take a closer look at the condition, what causes it, and why it’s so important to address it.
WHAT IS ANTERIOR HEAD SYNDROME?
As the name indicates, anterior head syndrome is a condition where the head is improperly aligned with the neck and shoulders in such a way that the head leans forward at an unnatural angle.
In a normal healthy spine, the head should be carried directly over the shoulders. This keeps the weight of the head over the body's center of gravity. Our heads are were designed to be supported by an ideal forward facing curve formed by the vertebral bones in the neck (cervical spine) - see the example of a textbook cervical film below:
This ideal neck curve predominately acts as a shock absorber for our head. In most cases, anterior head syndrome is related to poor posture. This condition is so pervasive it’s now commonly called “tech neck” and that’s a big clue as to how it’s caused. People who spent a lot of time reading, sitting, and performing other activities that cause the head to shift/tilt forward are very commonly found to have this condition. Here are some of the common causes that can lead to AHS:
Spending a lot of time at a computer or desk.
Spending a lot of time looking downward such as when using a cell phone to send text messages.
Poor posture while watching television or playing video games.
Sleeping with your head raised too high (inadequate pillow).
Sports that involve looking downward such as hockey, golf, baseball etc.
Carrying heavy backpacks or luggage - forces head too far forward.
Weak neck and back muscles.
The average person’s head weighs between 9 and 10 pounds. Did you know that for every one inch you carry/tilt your head forward from your center of gravity, the head effectively weighs ten more pounds? That means if your head is 1 inch forward, your brain perceives that it weighs 20lbs. 2 inches forward, then 40lbs etc. Properly supported with correct posture and good cervical curvature, the head should feel fairly weightless, however, when shifted forward, your body will feel every pound of it, pulling and tugging your neck and upper back out of position. Here's a visual, notice how the postural change isn't only happening in the neck and upper back, there is a compensatory effect in the lumbar spine as well (hips forward typically.)
The result? For a “lucky” few, anterior head syndrome will not present any symptoms. Be mindful this allows those people to continue to do the things that result in this condition in the first place. A lack of pain doesn’t always mean that things are ideal.
For most of us, a vast array of symptoms will present. And if left untreated, the damage can spread to the rest of the body. Initially, the symptoms will begin with the obvious ‘forward head’ associated with the condition, followed by an inward rounding of the shoulders. As the shoulders curve inward, the muscles of the neck and back will begin to be impacted by the unnatural ‘pulling’ forces of the weight of the head jutting forward.
Pain in the neck, shoulders, and eventually pain that radiates out to the upper, middle and lower back. Left untreated and uncorrected, the patient can expect the following additional symptoms in their future (there's a lot on there but I encourage you to read it):
Why is it that Anterior Head Syndrome causes the myriad of health problems listed in the "Secondary Conditions" figure above? Well, when the head shifts forward from the body's center of gravity, the spinal column in the neck elongates and straightens. Your spinal cord goes along for the ride as well given that it's living inside the spinal column. Harrison et al have clearly shown that loss of the cervical (neck) curve alters the mechanical properties of the spinal cord and nerve roots, which may change the firing patterns of the neurons (nerve cells) that comprise these structures.
This means that a distortion, loss or compromise of the normal cervical lordosis (forward curve) can and does have implications with subsequent organ function to some degree. A research paper published by Morningstar and Jockers supports this, demonstrating that correction of anterior head syndrome and restoration of the cervical curve was correlated with increase in pulmonary function. Improving the patients neck curvature showed improvements with their lung function. That's the bigger idea when it comes to all of this, aside from how your posture "looks" we need to really be mindful of the impact to other vital systems of the body.
Loss of the cervical ideal curve also causes unnatural stresses and load on the vertebral bones in the cervical spine. Wolff's Law of Bone Adaptation states that the body will lay down new bone in an area of stress or strain in order to strengthen it; research has shown that this process results in arthritic bone spur growth in the cervical spine. This is a really smart adaptation and “protective” response our body has. The problem is when these bone spurs grow into and negatively impact the spinal nerves and/or the spinal cord itself. Anterior head syndrome is a structural shift in the spine that causes an increased load to our spinal joints. Arthritis is one of the many secondary conditions that result from these shifts. When the bone spurs are large or pose a great threat to the surrounding nerve tissue, things like surgery can be a necessary intervention.
In conclusion, Anterior Head Syndrome is a postural problem that occurs in patients who perform repeated movements and activities that cause the head to shift and tilt forward. This unintentional “posturing” eventually teaches our brain and nervous system that this is your new “normal” when it in fact it should not be. Correcting Anterior Head Syndrome with structural chiropractic care is an important step towards restoring and protecting your spine’s normal structural and functional alignment. Most importantly though, improving AHS will positively impact your nervous system and help you to maintain optimal health and wellness. If not corrected, the results can be debilitating.
1. https://pubmed.ncbi.nlm.nih.gov/10395435/
2. https://www.treatingscoliosis.com/images/downloads/JPMFH-2009-1026_respiratory.pdf
3. https://pubmed.ncbi.nlm.nih.gov/19369754/