Fig. 1

Facial landmarks used in the classical facial metrics. Averaged Maasai portrait. Single landmarks: Gl—glabella (midpoint between the center points of the lower eyebrows' hairlines); N—nasion (midpoint between the highest points of the eyelids); Sn—subnasale (the midpoint of the base of the columella); Ls—labiale superius (the outermost point on the upper lip vermillion in the midsagittal plane); Sto—stomion (the point in the midsagittal plane where upper and lower lips vermillions meet); Li—labiale inferius (the outermost point on the lower lip vermillion in the midsagittal plane); Gn—gnathion (the lowest point of the chin in the midsagittal plane). Paired landmarks: Zy—zygion (the most lateral point of the zygomatic arch); Go—gonion (the most inferior and lateral point on the external angle of the mandible); Ch—cheilion (the outer corner of the mouth); Al—alare (the most lateral point of the nasal wing); Ex—exocanthion (the lateral point of the eye fissure); En—endocanthion (the medial of the eye fissure); Ps—palpebrale superius (the highest point of the free margin of the upper eyelid); Pi - palpebrale inferius (the lowest point of the free margin of the lower eyelid)