Fig. 1

H-Z method for bone block height assessment. A The apex of the coracoid process (point P) is located between the 4 o’clock and 6 o’clock lines on the oval, indicating that the bone graft is in the correct position. B Point P is located below the 6 o’clock line, indicating too low bone graft position. C Point P is located above the 4 o’clock line, indicating too high bone graft position