The Anatomy of Directing: Skull & Atlas

THE ANATOMY OF DIRECTING

Part of the Da Vinci Project, this series of posts will clarify anatomical points for the purposes of functional mechanics and directing.  Click on a picture below to zoom in. If you’re new to directing, check out this post, or the book, Neurodynamics: The Art of Mindfulness in Action.

Part 2: The Skull & Atlas

spine and vertebrae examplesAnother critical feature of the spine is its upper end where it articulates with the skull. The upper part of the spine, or cervical region, consists of seven vertebrae whose main job is to support the head. Because these vertebrae only have to support the weight of the head, they are smaller than the solid and chunky thoracic and lumbar vertebrae that support the weight of the entire trunk.

The most important cervical vertebra is the very first one, called the “atlas” because, it supports the globe of the head as the Greek titan Atlas supported the Earth on his shoulders. 1d-Atlanto-occipitalThe atlas vertebrae forms a joint with the base of the skull called the atlanto-occipital (or AO) joint, where two bumps on the base of the skull sit nicely in two concave depressions on the atlas. We nod our heads by articulating at this point.

But where exactly is the AO joint–that is, the place where the head actually sits on this topmost vertebra of the spine? When asked, most people point to the back of the neck, indicating a point much lower than the actual joint. One reason for this misconception is that, because we think of the head in terms of the face, we forget that the base of the skull is not the jaw (which is a separate bone!) but much higher up, near the cheekbones and practically at the level of the eyes.

Click on the picture below to zoom in.

Atlanto Occipital Joint and captionsIn practical terms, this means that the upper spine is much longer than we think, extending up much higher than the base of the jaw, to a point between the ears. It also means that the jaw is not part of the head but hangs as a separate bone from the base of the skull, and that the skull itself includes only the upper face and forehead.

We can thus see that the spine is much longer at its upper end than we realize, extending nearly to the level of the eyes. Just as we have a shortened conception of the spine at its lower end (as discussed in Part 1 of this series), we have a shortened conception of how far it extends at its upper end. We’ll revisit this issue further in a separate post when we look at the “forward and up” direction of the head, which is intimately connected with the relationship of the head to the spine where the head nods on the atlas at the AO joint.

 

Exercise: Find your AO joint

Step 1: Place your thumbs in your ears with your fingers extending forward toward your face. Let your fingers touch, wrapping around your face such that your pinkies are just underneath your nose and your other fingers touch the bridge of your nose and your forehead.

Step 2: Imagine that a pin has been inserted right between your thumbs and that your skull nods at the level of that pin. Your fingers are the skull itself. Use your thumbs and fingers to nod your head lightly at the level of the pin, where your thumbs are.

It is very useful to understand this because most of us have a shortened concept of the neck which corresponds to actual shortening of the neck and pulling back of the head which is our habit. Clarifying conceptually where the head sits and moves on the spine helps to establish a more accurate concept of how long the neck is, and enables us to gain more freedom and mobility in this region.

It’s also important to note where the skull sits on the spine when considering depth, or the front-to-back axis. The spine does not run along the back of the neck and into the back of the head at all; there’s quite a lot of muscle and connective tissue there, which is why you cannot feel the bony processes of the spine the way you can in other parts of the back. traps, scm, cervical spine and skullThis picture shows how the spine moves forward, making room for big muscle attachments that fill in that space under the occiput (many of which are not shown here) and then balances the skull from a more centered location, just behind the jaw. Again, the ears are a great way to conceptualize this. Touch your ears and imagine your spine coming up and articulating with the skull right at that point, in the center of your neck rather than along the back.

 

Exercise: Directing “up” **

This directing exercise demonstrates how an inaccurate conception of our anatomy can change how we direct, and affect our use.

skull with up arrowStep 1: Go into semi-supine position, lying on the floor with your knees up and feet on the ground. Put some soft books under your head for support and notice the bony point where your head touches the books. This is your occipital protuberance.

Step 2: Imagine that your spine runs along the back of your neck, ending at the the occipital protuberance, and then direct your head “up” or away toward the wall and out of your spine and back. Notice what happens, and any movement that takes place. You may find that this thinking extends your neck from the back, taking too much curve out of the cervical spine, shortening in front, and pulling your head forward and down.

spine, head and up arrow

Step 3: Now, reimagine your spine as running up the center of your neck and into your skull at the point of your ears. Direct along that line, and up through the center and crown of your head. What do you notice? This sensation of “up” is very different from the former, and allows all the muscles (front and back) that attach to the head and neck to truly lengthen out of your back.

**caveat: while the back of the neck often does need to lengthen quite a lot, this is more related to the “forward” part of the “forward and up” direction which we will cover in a later post, so as not to confuse the two.