Thoracic and Trunk Mobility

Thoracic and Trunk Mobility

The thorax is the major player in mobility of other joints in the body, the position of the thorax drives positions everywhere else in the body. First let's define what the thorax consists of, it is the part of the body from the neck down to the bottom of the ribcage, sternum, and in the posterior is the thoracic spine. For the trunk it is from the neck down to the top of the pelvis so it will include the whole thorax and the lower abdomen, and lumbar spine. The muscles that attach to the thorax and the hips are the major stabilizers of the trunk, and the muscles we will need to facilitate to control the mobility of the trunk and thorax. The thorax is two sided; a left ribcage and a right set of ribs, underneath the cage is where it all happens and drives us into our pattern. Looking inside the ribcage we have a heart inside the left rib wall that takes up space in the left thorax, on the right side we have a liver, and three lobes of lung tissue (compared to 2 on the left). One of the big drivers of the asymmetrical thorax is the diaphragm, the right hemi diaphragm is larger than on the left and the attachments are bigger and lower on the right side compared to the left. (PRI Reference).  This creates a dynamic dominance to the right side, the hips rotate to the right, the thorax and abdominal are oriented to the right and rotated back to the left to compensate. 


With these influences under the rib cage it affects our range of motion of the trunk, it is rotated to the right which limits right thoracic rotation and right trunk rotation, it can limit side bending, flexion and extension (bending forward and backwards) ROM. With the limited ranges of motion the body compensates with many strategies, the big one that is seen is tight, tonic and toned up muscles that do not shut down. They create certain pulls on the individual ribs and spine and re-orients bones and posture and influence air flow and breathing. That's where many can see pain in the back,  pain to the hips and leg joints or the shoulder joints, or neck. When the hips and the thorax are in a state of extension the pull of the hip flexors and diaphragm pull the lumbar (lower) spine forward which causes the ribs to elevate and the position of the abdominals to be lost so they cannot have an influence on the ribcage to do their job.


To gain control of correct trunk and thoracic mobility we have to address the asymmetrical rib cage and the muscles that act on the ribs. The right ab wall is the strong side with the liver and diaphragm attachment on the right make the right abdominals stronger and better positioned, so in order to get neutrality through the thorax we need to turn on the left abdominals to pull the ribs on the left down. When thinking of abdominals most people think of a 6 pack and the traditional ab workout, from now on those muscles are useless to us, we want to engage the internal/external obliques and the transverse abdominus to gain respiratory control and ribcage control. We must engage the left ab wall to inhibit our right side dominant pattern and be able to maintain the position and muscle engagement as we take an inhale in and exhale the air. We will take the 90-90 Hip lift with right arm reach, we need to be able to engage the obliques to act on the pelvis and then act on the ribcage as they act together they create the optimal position we want, while keeping the position we take a breath of air in maintaining the rib cage position this will neurologically set the brain to new position and train the brain to be able to maintain this position and gain better posture. Another exercise we like to use is the Wall Short Seated Reach, that helps get the ribs to an exhaled position and be able to create tension through the abdominals and be able to move air in that position.

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