Rib Articulation Significance in Thoracic Spine Mobility
by Taylor Lewis
There are two things we fight against every day: ageing and gravity, no matter the case. As we age, the range of motion in the trunk and shoulders decrease to a greater extent than the lower body (Medeiros, Araújo, & de Araújo, 2013).
Now, everyone is different and internal factors, such as genetics, and external factors such as lifestyle will play a role, but if we were going to quantify and generalize the trunk and shoulders, then time and gravity will win this battle.
We have learned thoracic spine mobility drills that take the spine through flexion, extension, and rotation to reduce the rate of decline in range of motion over time. We forget, however, that each rib articulates at two points on a thoracic vertebra, the costovertebral and costotransverse joints.
There are 24 totals ribs, and if you exclude ribs 11 and 12 due to having only one articulation, and focus on the posterior rib articulation to the thoracic vertebrae, you have 40 feasible joints that have a movement manipulation to the thoracic vertebrae. This means there is a potential to improve thoracic mobility by focusing on ribcage mobility.
Each division of the thoracic cage—upper region T1-T4/5, middle regionT4/5-9/10, and the lower region T9/10-T/12—has a unique movement capability to allow the lungs to expand. For example, during the coupling motion of inspiration (thoracic flexion to thoracic extension), ribs 1-5 have an anterior-posterior expansion shifting the sternum forward with elevation, ribs 6-10 swing outward medial to lateral with an inferior translation at the costovertebral and costotransverse joints creating an upward push against the rib above. This is reversed during expiration (thoracic flexion).
During left axial rotation, the left ribs posteriorly rotate, glide and roll anterolateral (flare up), while the right ribs anteriorly rotate, glide and roll posteromedial (Lee, 2015). When you raise one arm overhead, the spine and ribs laterally flex to the same side. All this means is that when the spine extends, flexes or rotates, the ribs are there to help guide motion.
Integrating exercises that target anterior-posterior upper thoracic cage expansion and medial-lateral lower thoracic cage expansion provides an indirect opportunity to work on gross thoracic spine mobility.
Remember, the ribs directly influence the thoracic spine and influence the osteokinematics and arthrokinematics properties of upper body motion at a degree we often forget. If you work on thoracic spine mobility, don’t forget to include rib positioning.
If thoracic spine motion is limited, checking rib positioning can create insight into what is actually limiting the range of motion. Rib fractures, slipping rib syndrome, or a respiratory illness could be the reason thoracic spine mobility is limited.
Upper body mobility will naturally decrease faster than lower body mobility as we age. Time and gravity are not on our side. This means we need to combat it with the right tools to decrease the decline. The thoracic spine and ribcage are a unit. Don’t isolate one; focus on attacking spine mobility indirectly through the ribs and directly at the thoracic spine.
Lee, D. G. (2015). Biomechanics of the thorax-research evidence and clinical expertise. The Journal of Manual & Manipulative Therapy, 128-138.
Medeiros, H. B., de Araújo, D. S., & de Araújo, C. G. (2013). Age-related mobility loss is joint-specific: an analysis from 6,000 flexitest results. Age, 35(6), 2399–2407.