What is one possible cause of unequal chest movement in a patient?

Unequal chest movement in a patient can occur when there is a disruption in the normal expansion of the lungs or the chest wall. One significant cause is post lung resection, which involves the surgical removal of a part of the lung. This procedure can lead to reduced lung volume on the affected side, resulting in decreased excursion during respiration. Since the lung on the resected side has less tissue to expand and contract, it will move less compared to the non-resected side.

Both atelectasis, which is the collapse of lung tissue, and pneumothorax, where air enters the pleural space causing lung collapse, can similarly lead to unequal chest expansion. Each condition alters normal lung mechanics, but the option of post lung resection provides a direct instance where surgical intervention has clearly caused a structural change impacting chest movement.