Fig. 2
From: Horizontal change of philtrum after orthognathic surgery in patients with facial asymmetry
Reference points and lines for measurement of the philtrum position deviation on a frontal view of a clinical photograph. Line a: interpupillar line as the horizontal reference line. Line b: facial midline perpendicular to line a and through the interpupillar midpoint. UPC: upper philtrum center as the midpoint of both the upper end of the philtrum ridge just below the columella. LPC: lower philtrum center as the midpoint of both the lower end of the philtrum ridge just above the vermillion border. LLC: lower lip center as the midpoint of the lower lip between both mouth corners