Glossary of Terms in Otolaryngology

Zero Meridian Line (of Gonzales-Ulloa)

  • The Zero meridian line, as described by Gonzales-Ulloa, is used in facial analysis to assess the aesthetic profile. It is most commonly used to assess chin projection.1
    • The Zero meridian line is defined by drawing a line perpendicular to the Frankfort horizontal plane that intersects with the nasion.
  • The relationship between the Zero meridian line and the pogonion (the anterior-most point on the chin) can be used to evaluate the position of the chin.
    • In the aesthetically pleasing profile, the pogonion should lie on or immediately posterior to the Zero meridian line.2

Zero Meridian Line of Gonzales Ulloa

  1. Bailey, Byron J., et al. “Chapter 170: Preoperative Evaluation and Facial Analysis in Facial Plastic Surgery.pdf.” Bailey’s Head and Neck Surgery - Otolaryngology, 5th ed., Wolters Kluwer, Lippincott Williams Et Wilkins, 2014. ↩

  2. Arroyo, Helena Hotz, et al. “Clinical evaluation for chin augmentation: literature review and algorithm proposal.” Brazilian Journal of Otorhinolaryngology 82 (2016): 596-601. ↩

Last updated October 28, 2022
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