This is the first of a whole series of articles that will start with a ‘nod of a head to the atlanto occipital joint’ before systematically tracing the joints all the way down to the big toe. Although anatomy can be a little bit technical at times stick with it and play with some of the movements and you will start to feel the words translate into your own body (the best anatomy text book on the market!)
Enjoy the ride and here we go…..
Affectionately called the OA joint – the occiput (or back of the skull) sits like a foot ball on top of the 1st cervical vertebrae (the atlas). The Atlas has 2 cup shaped facets which allows the skull to gently rock and nod into flexion (chin pulled back towards neck) and extension (chin poking out). The two articulations are surrounded by joint capsules which effectively shrink wrap the joints for extra stability. These capsules often become fibrotic and stiff due to prolonged postures or trauma and subsequently limit our movement potential and the ability for the muscles on top to lengthen and shorten.
“When the occiput flexes on the atlas its convex joints glides in the opposite direction to the movement of the bone.”
In English this means that when your skull nods into flexion the condyles of the occiput glide backwards, elongating the posterior capsule and during extension the condyles glide forward stretching the front of the capsule.
When assessing this joint I often find the back of the capsule is tight which restricts the ability to lengthen the back of the neck. If you are sat at a computer all day and find yourself rubbing your thumbs into the back of your neck to loosen things off you will know what I mean .
As well as flexion and extension we also have a few degrees of side bending and rotation at the joint. If we side bend the head to the right the occiput rotates to the left (we call this type 1 coupled motion) and during flexion this will emphasise the stretch on the back of the capsule on the left as well. If one side of the capsule is tight from a head trauma or a wonky work station set up, it can effect this coupled motion at the OA joint and have a subsequent knock on effect through out the rest of the body.
Top tip – for any muscle geeks check out the tone in the sternocleidomastoid muscle whose concentric muscle action can create this same coupled motion of rotation and opposite side bending.
Word of warning – if you have experienced a traumatic injury such as a whiplash or concussion or you are suffering from rheumatoid arthritis, you may have instability around this area so mobilising it would be a bad idea. Make sure you get checked out by a qualified health care practitioner first who can assess your upper neck complex.
To open up the OA joint my favourite go to is the sagittal cog exercise. To start with lie on the floor so you have feed back from the ground and start to gently rock your pelvis forward and back wards (anterior and posterior tilt). Assuming you have a beautiful chain reaction of joints that can open and close you will start to feel your skull nodding in time with your pelvis. If all is feeling well nod one side of the pelvis forwards then the other and feel how this emphasises one OA joint over the other. Voila a DIY assessment to check your own mobility. If one side feels stiffer try rotating your head 30 degrees to that side and then continue your pelvic tilts. This will line the facet joints up with gravity and allow you to really mobilise into the area. If it still feels a bit sticky then nothing beets a pair of well trained hands to gently tease a little more range that can then be integrated back into movement.
Integrating from head to toe
Time to throw in a bit of Anatomy in Motion gait mechanics. This always helps me to make sense of how the body functions as a unit and why it adapts to keep going.
There are three cornerstones that I always cross reference when assessing and treating, these are the heel bone (calcaneus), the pelvis and the skull. What ever phase of gait we are in, these 3 bones always do the same thing. As the skull mainly nods on the axis to keep your eyes level with the horizon (think about bobbing on a horse while looking straight ahead) I like to checkin with the pelvis to see if it can tilt anteriorly and posteriorly and the heel to see whether it can plantarflex and dorsiflex (this is basically the standing up version of the sagittal cog above).
There have been many occasions when one of these three have disrupted this harmonious relationship causing the others to move more or less in response. Here is a short video showing this relationship in a split stance.