When I started to do yoga, my teachers very rarely mentioned the role of the spine in asanas although it is equally important to breathing. There are 31 pairs of spinal nerves originating from the spinal cord. These nerves are like communication channels or vessels between organs and the brain, part of the autonomous nervous system. Yoga poses move the spine it in different directions to keep vertebrae and discs between them healthy so that there is enough space between the adjacent vertebrae for the nerves to emerge without any impingement.
But the vertebral column is not an elastic band that can be forced in all directions without any concern of the range. Many things can go wrong if one does not know what is the average amount one can twist and turn from the cervical spine (7 topmost vertebrae) the thoracic spine (12 mid back vertebrae) and the lumbar spine (5 lower back vertebrae).
A very common mistake is to overexploit the part of the spine that is most flexible. It often tends to be the lower back, which develops when babies start to walk. The cervical (develops when the baby starts to lift the head) and thoracic (develops already in the womb) spine have already got their curves by then. The lower back is not propped with the rib-cage unlike the mid back and it is therefore more flexible and exposed to overexploitation.
*The below table illustrates the approximate range of a healthy upper, mid and lower back. If you are a ballet dancer, your range is more. If you are an office worker, your range is less. When you move your spine, you tend to use other parts of the body as well. For example, when bow forward, you usually bend from the hips, too. Please note therefore that the below table shows the spinal range only.
| Part of the spine | Flexion (forward-bend) | Extension (back-bend) | Rotation (twist) | Lateral flexion (side-bend)
|
| Cervical (7 top-most vertebrae) | 45⁰ | 75⁰ | 50⁰ | 35⁰ |
| Thoracic (12 mid-back vertebrae) | 40⁰ | 25⁰ | 35⁰ | 25⁰ |
| Lumbar (5 lower back vertebrae) | 60⁰ | 35⁰ | 5⁰ | 15⁰ |
| Total range (approximate)* | 145⁰ | 135⁰ | 90⁰ | 75⁰ |
Source: Various sources – books and internet – consulted
Why are those numbers important?
Take the rotations such as Ardha Matsyendrasana (Half Lord of the Fishes Pose) or Supine spinal rotation Supta Matsyendrasana. Even though the lower back is flexible both in the back and forward bends, it has a very little range in rotations, only about 5⁰. But often yoga students force the rotation from the lower spine forgetting that most of the 90⁰ comes from the cervical spine (50⁰) and the thoracic spine (35⁰). How would you feel if someone were forcing you to put your leg behind your neck when you know that you cannot? This is how your lumbar spine feels like in rotations where you force it to do more than it can.
In standing rotations such as Parivrtta Parsvakonasana (Revolved Side Angle) or Parvirtta Utkatasana (Revolved Chair Pose) the same rule applies – rotate from the upper and mid back rather than lower back. Think of distributing your weight equally between the back and front and keep your hips level. This coaxes the thoracic and cervical spine into performing the rotation. When you ignore your biomechanical range the compensation patterns which initially are just physical, will gradually evolve into mental tensions. Usually we focus on the reverse – mental turning into physical – but unawareness of proper alignment can do as much harm in the long term. And office people tend to have sensitive lower backs so why do more harm than sitting wrong?
Another important issue often neglected in yoga practice is to observe and respect (or correct) the pelvic tilt in our bodies. Seemingly simple seated hip opening such as Siddhasana, Sukhasana and Padmanasana (Lotus Pose) can pose a great challenge to many people. The reason being that we are office people and rarely practice external hip rotations which means that most grown-ups have become tight from the hips. Due to a lot of sitting on chairs the angle of the pelvis is often out of the healthy range. There can be multiple reasons for excessive pelvic tilt – we may have slack abdominal muscles or erector spinae or there could be a tight group of muscles called iliopsoas which joins the upper and lower body and hinders sitting with the right angle.
If if you add tightness in the muscles supporting hip opening, you notice yoga students sitting on the mat with hunched shoulders and kyphotic back. With a wrong posture it is not possible to meditate or relax in seated hip openings. When the spine is well-balanced and somewhat lengthened above the pelvis, you are saved from overly tight back and neck muscles which compensate for an unequal distribution of the weight in seated poses. When the bone- lifts-the-bone ergonomics takes over from muscle-lift-the-bone it will ease the mind. In addition, the back rejoices over the feeling of release as the body can hold itself upright with minimum exertion.
There are lots of yoga poses where you have to be propped up with dozens of things to get the pose right. Fortunately for the pelvic tilt it can be easily corrected – you just need a blanket or two under your sit bones. But for some reason I keep seeing many hunched shoulders and kyphotic backs on the yoga mat …and no blankets.
Next time I will continue with explaining how one can harm the health of joints with torque (for example in Warrior I and II poses) and what are the dangers with a pose often used to challenge yoga students and stretch the IT (iliotibial) band – the Pidgeon pose.
Stay tuned!
More reading:
https://letsbands.com/en/blog/pelvic-tilt-hollow-back-back-pain/
http://www.mbmyoskeletal.com/learning/pelvic-tilt/ (Manchester-Bedford Myosceletal)
http://khourychiropractic.com.au/uncategorized/hips-dont-lie/
Twisting the spine in yoga and in life http://corewalking.com/twisting-the-spine-in-yoga-and-in-life/