What is it that you can feel when you are moving your spinal column?
You can feel the muscles that work on your spine.
Once you get used to feeling your muscles, you can then use them as references for learning to feel the individual vertebrae of your vertebral column.
You can think of your ribs as levers for twisting your thoracic spine and bending it. The muscles that act on the thoracic spine directly or via the ribs include the intercostals, obliques, rectus abdominus and spinal erectors.
A simple exercise to practice feeling your thoracic spine and ribcage is easy breathing. It helps to train your intercostals. For more emphasis on your spinal erectors you can try this seated twist exercise.
And one other exercise that you can use to practice feeling the individual vertebrae of your thoracic spine while at the same time training your spinal erectors is locust pose.
Rather than just lifting your head and ribcage while doing locust, focus on bending your cervical and thoracic spine backwards. To develop your spinal column awareness even further, focus on bending your thoracic spine backwards one joint at a time.
In the case of your ribcage, the muscles that move the ribs relative to each other are the intercostals.
These muscles can be used to lift and lower the ribs while keeping the vertebral column immobile. However, the degree of movement can be increased signinficantly if you bend your spine backwards and forwards at the same time as you lift and lower your ribs.
These muscles also work on both the ribs and thoracic spine in twisting movements. It is not possible for the ribs to move independently of the spine in a twist. And so you can use your intercostals and abs to twist both your ribs and to turn your thoracic vertebrae relative to each other.
Note that where the intercostals turn the ribs (and thoracic vertebrae) relative to each other, the obliques can be used to turn the ribcage relative to the pelvis. They are also active in turning the lower ribs relative to each other.
When actively bending your ribcage backwards you may be able feel your spinal erectors activating and relaxing as you bend your spine and then relax. These muscles run up and down the back of your body along either side of the entire spine.
In order to use them to bend your thoracic spine backwards, focus on the back of your ribcage and focus on bending it backwards. With practice you'll actually be able to feel your thoracic spinal erectors activating. If you are having difficulty, first try to activate your lumbar spinal vertebrae and then carry the contraction upwards so that then you activate your thoracic spinal erectors. (The seated twist exercise has more instuctions on this.)
One thing that is important to realize with respect to the spinal erectors is that they can be divided into specific groups. More importantly you can choose how you activate your spinal erectors so that you bend all of your spine backwards or only parts of it.
As an example, while laying down and doing locust you could focus on using your spinal erectors just to bend your cervical spine backwards.
You could also focus on just your upper thoracic spine or on your entire thoracic spine.
To feel the part of your vertebral column that connects your head to your ribcage, you can turn your head to one side. You can then focus on feeling your cervical vertebra and you can focus on turning them relative to each other and your ribcage.
When bending your neck to the side you can do the same thing.
Note that there are 7 cervical vertebrae. The uppermost ends at a point just level with the bottom of your ear hole.
Why bother knowing how many cervical vertebrae you have? Well if you can feel the base of your skull and the top of your ribcage you can count of your vertebrae as an aid to feeling them. And you can focus on moving them one at a time. Say you are bending your neck backwards. You can start of with your head, then tilt C1 backwards, followed by C2. Ideally, by the time your reach C7, you are at the top of the spine. If not, just try again.
Since the thoracic spine is the base of the cervical spine, you can give your neck a good foundation for twisting and bending by lifting your chest and straightening the upper part of your thoracic spine. This might be especially important when bending your neck backwards. (Do this slowly so that it is comfortable on your neck and so that you can stop easily if you feel like you are hurting your neck.)
With practice what you may find is that by pulling your head back and up you can actually help your chest to open. This action will also straigthen the upper part of your thoracic spine.
The pelvis is at the base of your vertebral column. If the ribs can be used as levers to act on the vertebrae of the thoracic spine, the pelvis can be used as a lever to act on the sacrum.
In some instances you might want to think of the pelvis and sacrum as one extra large vertebrae that you can use for leverage on the vertebral column. In other instances, say like while bending backwards, it may be advantageous to think of the sacrum and pelvis as separate pieces that can move at the SI Joint (Sacro-Iliac) relative to each other.
I mention backbending the vertebral column in particular because I believe that this is one action which can be made easier if you allow your sacrum to move relative to your pelvis. You can learn to feel the sacrum moving relative to your pelvis at the SI Joint and with some understanding of the muscles that act on the sacrum you can also learn how to control the sacrum relative to the pelvis.
One of the ways that you can feel your pelvis is by rocking it backwards and forwards. If you haven't already done so, check out the seated twist excercise. The first part of this exercise involves rocking your pelvis backwards and forwards.
You can use this same exercise to practice feeling your lumbar spine and the rest of your vertebral column. (It bends backwards when your tilt your pelvis forwards...)
Your lumbar spine connects your pelvis to the ribcage. It allows them to move relative to each other. It also keeps them apart. It gives them each room to move relative to each other.
The vertebrae of the lumbar spine (there are five in all) can bend from side to side and back and forwards relative to each other but because of the way that they inter connect, rotation is limited. That being said you can still focus on twisting the lumbar spine when doing spinal twists.
Because of the lumbar spine, the sides of the pelvis and ribcage can move towards each other and away from each other.
To get used to the actions of the lumbar spine, practice