As we've discussed before on the Vital Blog, concussions are quite complex and many issues play into how we manage and prevent the injury - but where does Craniocervical Junction, or CCJ for short, come into play? We will discuss 3 major factors that play a role with CCJ and concussion.
What IS Craniocervical Junction?
Craniocervical junction is a term used to describe the interface between the skull and the cervical spine - more specifically, it includes the occipital bone and the first and second vertebrae (C1 & C2).
As we've discussed frequently, concussions are complex because it is essentially impossible to have a head injury without a neck injury. With any concussion, there is a hit to the head or a blow to the body - something that causes so much force that the head is jerked and the brain knocks against the inside of the skull. Studies show that it takes at least 95 g's of force to sustain a concussion but as little as 4 g's of force to sustain a neck injury; so is it really surprising that, more often than not, both injuries occur?
A 2016 Review on major traumatic brain injury (mTBI) and cervical spine explains that it is widely accepted that cervical spine involvement in concussion is clinically accepted. In fact, 33% of concussion DO NOT resolve on their own.
When you think of your neck, oftentimes you think of one thing - the seemingly small part of the body connecting your head to your torso. However, the neck should really be divided into 2 sections. The lower two-thirds of the neck are fairly stable, however, the upper third has a completely different structural anatomy AND a different function than the rest of the spine.
The Society of Neurology Annual Meeting in Florida specifically discussed the significant role of the C1 and C2 vertebrae in sports concussion. The transverse and alar ligaments stabilizing this area have high collagen and low elastin content which makes them more vulnerable to injury and increases the possibility of upper cervical instability. The upper cervical spine and craniocervical junction has the MOST impact and has major influence on brain function following a concussive force.
So we know the neck is involved and we know the upper 1/3 is a vital component but the last thing we need to focus on is the why. There are at least 2 main mechanisms that play a role in concussion management in regards to craniocervical junction. An injury will cause a shift in the structure, a twist or imbalance between the skull, C1 and C2. This shift represents whiplash associated symptoms.
Brain physiology can affect a number of things including fluid flow and sensory feedback from the body to the brain. These changes to brain physiology can cause many of the symptoms that we see in post-concussion syndrome.
Concussions are a lot more complex than people think and unfortunately, the symptoms and lasting side effects are more detrimental than most know of. It is important to stay educated on concussions, parallel injuries and injury prevention/management, ESPECIALLY if you have a young athlete susceptible to injury.