One of the difficulties with Anatomy for "movers" or for people who are interested in operating and understanding their body from inside of that body is that there is only one anatomy reference position, the "anatomical position."
In the anatomical position, the body is presumably supine, not affected by gravity, with the palms and head facing up.
This is great for anatomists and surgeons who are viewing the body as it is laid out on a table or slab. But it's a little bit limiting for athletes, yogiis, dancers or anyone else who is in their body and is interested in the details of using their body.
If you've ever written a web page and included links you know that you have to write a full web address to link to a page not on your website i.e. http://sensational-yoga-poses.com/anatomical-positions.html.
However if you are referencing a page on the same site (and in the same directory) all you need to include is the name of the page i.e. anatomical-positions.html.
In the spreadsheet program excel you can reference cell addresses when using formula or macros as absolute, using the a1 cell as absolute or you can use relative references, 2 cells up and 3 cells to the right from the current cell.
Imagine having to fly from New York to London, but instead of going direct you had to fly via Chicago or Houston.
That's more or less what we have to do with only one anatomical position as an anatomical reference.
While I'm not proposing that the anatomical position be ditched, I am suggesting that alternatives be created or that "movement" anatomists be given the option to create new references. Or they think of them themselves, stating the "starting position" or "reference position" clearly so that others know where they are starting from, and where they are going to (and what is being done to connect those two positions.)
The nice thing about the anatomical position is that it is clearly defined.
Whenever the anatomical position is used as a reference, if we know what the anatomical position is, then we know that position is our reference.
And that's an important point. We can create and use other reference positions so long as we clearly state what they are.
To explain supination and pronation we can use we can use the point of the elbow (the olecranon process) as a reference.
Supination, is where the forearm is twisted so that the back of the hand and the point of the elbow face the same direction. Pronation is where the forearm is twisted so that the back of the hand and the point of the elbow face ind different directions.
One idea that might be helpful in creating "alternative" anatomical positions is the idea of "minimum energy" positions and perhaps "maximum length" positions.
As an example, there could be a standing upright anatomical position where the weight is centered over the fronts of the heels so that the front of the foot is still in contact with the floor. This is as opposed to having the weight on the back of the heels so that the front of the foot lifts, or having the weight forwards more so that they front of the foot or toes press into the floor.
In this position, the calcaneus and talus can be stacked vertically on top of each other when viewed from the back (stacked vertically in the sagittal plane).
In this position the feet would be hip width, the feet parallel.
How could "feet parallel be defined?
The outer edges could be parallel or the inner edges, or lines through the center of the heel and either the second or third toes could be parallel.
These can all be valid reference points so long as they are clearly stated.
Since we are on the topic of feet another reference position could refer to the shape of the feet themselves and the arches.
When the inner arch (the medial arch) is active, not collapsed and not lifted too high, then the knee points in the same direction as the second or third toe.
If the knee (and shin) are rotated outwards from this position that tends to lift the center of the inner arch higher while rotating it inwards tends to collapse the inner arch.
In this position the knees could be straight although it could be useful to have a knees slightly bent anatomical position.
(The challenge in the latter case would be defining how bent "slightly bent" is. One possibility, bend the knees enough so that it is easy to tilt the pelvis backwards enough that the lower back feels full.
Some of you might be objecting and saying that this is hardly an objective anatomical position. That's the point. As yogiis, athletes, dancers, martial artists, movers, we are in our bodies. We are controlling our bodies. And so it makes sense to create or use anatomical positions that can be felt or detected from inside the body.)
How would we define the position of the spine. Two options seem logical. There may be more, but the important thing here is that the positions be clearly defined.
In the "relaxed" upright position the head would probably be forwards, the chest sunk slightly, and the pelvis tilted forwards. (Anteverted?)
(As a side note I often get confused responses when I talk about rolling the pelvis forwards and backwards, Usually I demonstrate with a water bottle. If the pelvis is like a wheel, then rolling it "forwards" causes it to move forwards. That usually clears up the confusion.)
An alternative position would be a "spine maximally long" position in which the crown of the head is pushed away from the sitting bones.
The cool thing with these alternative references is that they can be initial points of research, what is the state of the body in this position. Which muscles are active or should be active? How do we "relax" in this position.
It can also be a starting reference for other positions.
One thing that is missing from the anatomical position is the effect of gravity on the upright standing body.
Without moving the feet we can shift body weight forwards so that weight is even on forefeet and heels.
We can shift the weight of the body forwards even more so that the toes press down.
At each position we can define the change in muscle tone relative to the first position.
Of course we also need to define how weight is shifted forwards. Does the legs and spine remain in a straight line or is the spine/torso kept vertical and "slid" forwards as one unit so that only the legs tilt forwards?
What happens if the weight is shifted onto one foot? In this position the other foot could still be on the floor. The torso would still be vertically stacked. (And the spine position would be specified, relaxed or maximally long!)
However, the weight of the body would all be on one foot. Here again positions could be defined. Weight on the front of the heel, weight even between heel and forefoot (calcaneus and head of metatarsals) or forwards enough that the toes press down naturally.
Having the unweighted foot on the floor would be a starting point, or reference point for other reference positions. The foot could be lifted straight forwards, or to the back. Or the knee could be bent and lifted while letting the shin hang down.
If body weight relative to the standing foot is specified we could then further define what happens to the standing leg and torso in this position relative to the starting position.
Other reference positions could include one where the feet are separated but the knees are straight and the spine vertical.
I'd suggest knees straight as a starting position because this is a minimal energy position.
One possibility is that one leg is forwards and the other is back with the back foot turned out.
How far would the feet be separated?
From front to back the legs and heels could form an equilateral triangle. (The distance between the heels could be the same as the length of a leg.)
Front side to side the heels could be hip width or on the same line. For this to serve as a reference position all that is required is that it be clearly defined. (going back to the front to back distance between feet, we might have to define what is meant by "the length of a leg.")
If the hips are relaxed then the weight of the body will cause the pelvis to turn towards from the front leg and away from the back leg. (if the right leg is forwards then the pelvis would turn to the right.)
This would be the "minimal energy" position.
An alternative would be to square the hips so that they face forwards as defined by the front foot.
With the minimal energy position and the facing forwards position, there's the possibility of figuring out which muscles activate to keep the pelvis square.
Another position is that which "lifts" the pelvis the most. For that the pelvis would have to be turn away from the front leg and towards the back leg until it was in the same plane as the heels and legs as a whole.
Another reference position would be with the feet separated and still parallel. From here another position could be with one foot turned out 90 degrees and the other foot turned in.
The feet could be positioned so that heels are on the same line or the heel of the turned out foot can line up with the instep of the slightly turned in foot.
Generally, with a foot turned out, the pelvis will turn slightly towards that foot.
But the position could be specified so that the pelvis faces the front or is allowed to turn toward the turned out foot.
In any of these foot positions, one knee or the other can be bent. The pelvis can be tilted forwards, or backward, tipped to the left or right, or rotated (twisted) left or right.
However, rather that using the anatomical position as the reference, we can use any one of the positions stated above as a reference. (Or clearly define the position we are using as a reference.)
The more we define other reference positions, the more we can use these positions as points of study, saying which muscles can and cannot activate. (Or which anatomy trains, or myofascial meridians.) More importantly, for yoga teachers, dancers, martial artists, everyday people, these positions can help them become more familiar with their bodies. They don't have to be a neuroscientist (or brain surgeon) to figure out how everything refers back to the anatomical position.
While I focused on leg positions as new anatomical reference positions for people who are operating their body from the inside, something similar could be done with the arms.
Arms forwards, arms up, arms out to the sides. All of these could be used as reference positions.
With arms forwards the palms could be facing inwards which means that the forearms are mostly supinated.
With arms to the sides, palms could e downwards which means that the forearms are neutral since the point of the elbow is in line with pinky side of the palm (the olecranon process is inline with the styloid process of the ulna so that the radius and ulna are parallel.)
With arms up the palms could again be facing inwards so that the forearms are in the supinated position (but perhaps not maximally supinated.) And the shoulder blades would ideally be moving outwards, away from the spine with the bottom tip (the inferior angle) moving outwards more than the top of the shoulder blade (the medial angle) so that the shoulder socket lifts higher than the inner edge of the shoulder blade.
With the option of different anatomical reference positions, anatomy could be used to help people better use their bodies as well as understand them.
As a yoga teacher, I'm constantly exploring new exercises, new ways of doing yoga poses.
There is no single "right way" of doing a yoga pose. Instead, there are options. And the better you are at "feeling" your body, the better you can get at choosing the right option for your body as it is now.
For any technique, the point of practice is to learn feel it and to control it, so that it can be used without thinking about how to use it.
And that is more or less the approach taken in all of my ebooks and videos. They help you to feel your body and control it so that you can work towards using it effectively in anything that you do.