Estimation of bone loss based on glenoid rim distances. En face view of glenoid is viewed on a CT scan. With use of intersection of longitudinal axis and widest anteroposterior diameter of glenoid, the bare spot is approximated on the glenoid fossa. A best-fit circle centered at the bare-spot approximation is drawn about the inferior two thirds of the glenoid (red). Distances from the bare spot to anterior rim (A) and posterior rim (B) are measured. The percent bone loss is calculated according to the indicated equation.