Overall chest expansion: Take a tape and encircle chest around the level of nipple. Take measurements at the end of deep inspiration and expiration.
Symmetry of chest expansion:
Have patient seated erect or stand with arms on the side. Stand behind patient. Grab the lower hemithorax on either side of axilla and gently bring your thumbs to the midline. Have patient slowly take a deep breath and expire. Watch the symmetry of movement of the hemithorax. Simultaneously, feel the chest expansion.