Picture a bow and arrow, forget the arrow, and remove the rope attached to the ends of the bow, and the bow will straighten up. Expand this to the spine, and more, the bones go where the tissue tensions pull them. This is a simplified model for Scoliosis.
The Spine is not one rod but segmented, 7 Cervical, 12 Thoracic, 5 Lumbar, allowing for tissues to attach to any of the vertebra, not just the ends, bringing localized bending. The vertebra are not smooth tubes but have lateral processes and a spinal process, allowing a slightly diagonal contact, producing a slight side bending or twist.
Adding more features, there’s a large ring at the base of the spine, i.e. the Pelvis, then the Ribs, and near the top two crossbars, the Clavicles and attached the Scapulae, and at the top the Skull.
Tissue attachments can now produce a larger lateral bending or rotational effect the further away from the spine, from Pelvis or Clavicle, Scapula or Skull.
Indeed, the tight tissues don’t even need to connect with the spine, consider a tissue linking the pubic bone to the Sternum, or any one attaching structure connecting with another attaching structure, the Spine will bend and twist.
There can be adjacent tissues reinforcing the tightness, often there are more than one tight tissue curving the spine, a localized bend could be the result of multiple tight tissues.
The result can be an intricately connected skeletal structure, and it can get worse, a bend between two adjacent vertebras can pinch the nerves exiting in between, the irritated nerve can lead to muscle tensions aggravating the tightness.
So what can be done about this? So far with only two clients, one gained some height and then stopped coming, now lives out-of-state, the other had no change in one session, but I noticed there was tight fascia on one side of the abdominal area while I had focused on the vertebrae, the lesson – find the tightest attachments then the next …