"My question regarding thoracic outlet syndrome is this: when doing the right or left arm reach after having restored rib cage position (all tests negative), should I be instructing them to keep their ribs on the ground even though they are reaching? Since after re-establishing position, the next step is to retrain the ribs to sit on the scaps (TS movement), should I instruct them to always keep the ribs back, and when reaching, only let the scaps and arm slide forward? Or, especially with a right arm reach, do we still want them to rotate the ribs to the left in order to keep ZOA on the left? A secondary question would be, why do we start with a left arm reach in a TOS client? The only resource I am going off is the article on the PRI website here about the football players with bilateral TOS, so I guess I was a little confused when after re-establishing rib cage position, the next exercise prescribed was a left serratus vs right tricep/serratus, as is outlined in the Postural Respiration matrix."
With regards to your questions, I would encourage you to keep the ribs on the ground when in a supine position as you alternately reach with either arm and hand. Yes you would want the athlete to reach forward while at the same time move the posterior rib cage posteriorly since you have established neutrality. You would want to emphasize left posterior mediastinum movement in the earlier process to engage the serratus anterior to move the ribs back on the scapula and the right arm forward to facilitate the right serratus anterior to move the scapula forward on the thorax. Again this would be early on in the treatment or strengthening program. Rotating the rib cage to the left with a right arm reach is fine as long as you do not allow the anterior ribs on the left to “pop” up too much, in the process. You start with a left arm reach to promote rib external rotation on the right and internal rotation on the left with left abdominal wall engagement. This facilitates left thoracic abduction and right lateral intercostal and left posterior mediastinal concurrent expansion. It also promotes LAFIR at the left hip, so that alternating activity with the hips can occur with proper left hip and rib cage integration, otherwise the disintegration will bias the LAIC pattern, and not the RAIC pattern. The left serratus anterior and left lower trap assists the mid to lower thoracic spine to rotate to the right, as the left serratus stabilizes the thorax during right spinal rotation from the left low trap and IR of the left ribs and assists moving the left ribs back during left rib IR. The right low trap and tricep retracts and posteriorly tilts the scapula as lower spinal rotation to the left occurs which promotes thoracic flexion and deactivation of the right latissimus.