Appendix D - Surface Angles, Planes, and Measurements: Definitions

Facial thirds

Upper third: Trichion to glabella

Middle third: Glabella to subnasale

Lower third: Subnasale to menton

Horizontal fifths: Five equally divided vertical segments of the face

Frankfort plane: Plane defined by a line from the most superior point of auditory canal to most inferior point of infraorbital rim

Nasofrontal angle: Angle defined by glabella-to-nasion line intersecting with nasion-to-tip line. Normal, 115 to 130 degrees (within this range, more-obtuse angle more favorable in female, and more acute angle in male patients)

Nasofacial angle: Angle defined by glabella-to-pogonion line intersecting with nasion-to-tip line. Normal, 30 to 40 degrees

Nasomental angle: Angle defined by nasion-to-tip line intersecting with tip-to-pogonion line. Normal, 120 to 132 degrees

Relationship of lips

To nasomental line: Upper lip, 4 mm behind; lower lip, 2 mm behind line from nasal tip to menton

To subnasale-to-pogonion line: Upper lip, 3.5 mm anterior; lower lip, 2.2 mm anterior Mentocervical angle: Angle defined by glabella-to-pogonion line intersecting with men­ton-to-cervical point line

Legan facial-convexity angle: Angle defined by glabella-to-subnasale line intersecting with subnasale-to-pogonion line; normal, 8 to 16 degrees

PEARL

Useful in assessing chin deficiency, candidacy for chin implant, chin advancement, or other chin alteration

Nasolabial angle: Angle defined by columellar point-to-subnasale line intersecting with subnasale-to-labrale superius line; normal, 90 to 120 degrees (within this range, more obtuse angle more favorable in female, and more acute in male patients)

Columellar show: Alar-columellar relationship as noted on profile view; 2 to 4 mm of col ­umellar show is normal

Nasal projection: Anterior protrusion of nasal tip from face

Goode's method: A line drawn through the alar crease, perpendicular to the Frankfurt plane. The length of a horizontal line drawn from the nasal tip to the alar line divided by the length of the nasion-to—nasal tip line. Normal, 0.55 to 0.60 (2,3)

Crumley's method: The nose with normal projection forms a 3-4-5 triangle (i.e., alar point-to-nasal tip line (3), alar point-to-nasion line (4), nasion-to-nasal tip line (5) (4). Byrd's method: Tip projection is two-thirds (0.67) the planned postoperative (or the ideal) nasal length. Ideal nasal length in this approach is two-thirds (0.67) the midfacial height (5)

Powell and Humphries "Aesthetic Triangle":

Nasofrontal: 115 to 130 degrees

Nasofacial: 30 to 40 degrees

Nasomental: 120 to 132 degrees Mentocervical: 80 to 95 degrees

REFERENCES

1. Tardy ME, Walter MA, Patt BS. The overprojecting nose: anatomic component analysis and repair. Facial Plast Surg 1993;9:306-316.
2. Ridley MB . Aesthetic facial proportions. In: Papel ID, Nachlas NE , eds. Facial plastic and reconst r uctive surgery. St. Louis : Mosby Year Book, 1992:99-109.
3. Crumley RL, Lamer M. Quantitative analysis of nasal tip projection. Laryngoscope 1998;98:202-208.
4. Byrd HS, Hobar PC. Rhinoplasty: a practical guide for surgical planning. Plast Recon.str Surg 1993;91: 642-654.