Which finding most strongly indicates adequate thoracic mobility during assessment?

• A. Observing rib cage expansion and thoracic extension/rotation in prone and seated positions indicates adequate mobility.
• B. Ribcage movement is not related to thoracic mobility.
• C. Thoracic mobility can be judged by lumbar spine alone.
• D. Mobility is only assessed during standing tasks.

Answer: (D)

Focusing on how the upper back moves in different postures reveals thoracic mobility. The strongest sign of adequate thoracic mobility is observing the rib cage expand and the thoracic spine extend and rotate when tested in multiple positions, like prone and seated. This shows the thorax is able to lengthen and rotate, not just that other parts move. Rib cage movement is directly tied to thoracic motion, so limited expansion indicates restricted thoracic mobility. Assessing mobility by the lumbar spine alone misses the true thoracic ROM, and evaluating it only in standing tasks can overlook restrictions that appear in lying or seated positions. In short, the combination of rib cage expansion with thoracic extension and rotation across different postures is the best indicator of adequate thoracic mobility.