All of the rib bones attach to the thoracic spine in back, and wrap around to to the breastbone in front. Known as the “rib cage,” it is effective at protecting the heart and lungs. But movement in the upper back, or thoracic spine, is naturally limited by the rib cage and its attachments.
The relationship between the spinal curves leads to a tendency for students to compensate or use “release valves” when making adjustments in one part of the spine. When a student is guided to lessen an excessive curve in the thoracic spine, for example, our intention is that she lengthen the spine. However, there may be a tendency to simply increase the curve of the lower back.
The mobility of the shoulders leads to vulnerability and often a need to focus on strengthening. In terms of using yoga asana for strengthening, traditional poses feature many “pushing” movements but few “pulling” movements, setting up a potential for imbalance.
Traditional asana tends to strengthen the shoulder’s “pushing” muscles, but not the opposing group of shoulder “pulling” muscles. For example, poses like Downward Facing Dog and Wheel / Upward Bow require pushing away from the floor. Since few poses require pulling against resistance, there is a potential of imbalance and weakness in the back of the rotator cuff. Pulling can be found in weight lifting and swimming. In asana, Catherine Guthrie notes that pressing shoulder into floor in Revolved Abdomen Pose and into the front leg in Revolved Side Angle Pose accomplish this action. (Jenni Rawlings and Catherine Guthrie)