https://www.youtube.com/watch?v=uHQWc5TH0NU
Step 1: Identify and mark the end vertebrae
Step 2: Open Measure App on iPhone. https://apps.apple.com/us/app/measure/id1383426740
Step 3: There are two options on the bottom screen, "Measure" and "Level". Choose "Level". This brings up the inclinometer.
Step 4: Place the iPhone's edge along the line drawn on the lower end vertebra.
Step 5: Touch the iPhone's screen somewhere in the middle. The degrees recalibrate to zero.
Step 6: Now move the iPhone's edge to the line drawn for the upper end vertebra.
Step 7: The reading on the iPhone will give you the Cobb angle.