Amount of Facial Asymmetry in a Spherical Coordinate System: A Comparison Before and After Orthognathic Surgery : Table 1

Table 1: Landmarks, reference planes and facial lines used for this study.

Landmarks	Porion (Po)	Highest point on roof of external auditory meatus
	Orbitale (Or)	Deepest point on infraorbital margin
	Nasion (Na)	Most posterior point on curvature between frontal bone and nasal bone in midsagittal plane
	Opisthion (Op)	Most posterior point on posterior margin of foramen magnum
	Cd_sup	Most superior point of condyle
	Cd_lat	Most lateral point of condyle
	Cd_post	Most posterior point of condyle
	Go_inf	Most inferior point of gonion area
	Go_lat	Most lateral point of gonion area
	Go_post	Most posterior point of gonion area
	Me	Most inferior point on symphysis of mandible
Reference planes	Horizontal plane	A plane constructed by right Po, right Or and left Or
	Midsagittal plane	A plane perpendicular to the horizontal reference plane and passing through Na and Op
	Coronal plane	A Plane perpendicular to midsagittal and the horizontal planes and passing through Op
Facial lines	Ramal height line	LineCd_sup-Go_inf
	Ramal lateral line	Line Cd_lat-Go_lat
	Ramal posterior line	LineCd_post-Go_post
	Mandibular body line	Line Go_post-Me