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Table 1 Explanation of the landmarks and measurements

From: Three-dimensional evaluation of hyoid bone position in nasal and mouth breathing subjects with skeletal Class I, and Class II

Measurement Definition Interpretation
H-Me The distance between hyoid bone and Menton point Hyoid bone position in relation to the mandible
H-EB The distance between hyoid boneand Epiglottis point Hyoid bone position in relation to the epiglottis
C3-H The distance between the 3rd cervical vertebrae and hyoid bone Hyoid bone position in relation to the 3rd cervical vertebrae
C3-Me The distance between the 3rd cervical vertebrae and Menton point This line forms the hyoid bone triangle combined with H-Me line, and C3-H line
H-C3Me The perpendicular line from hyoid bone to the line connecting the 3rd cervical vertebrae and Menton point The vertical height of the hyoid bone triangle. A positive value indicated a downward direction of the hyoid triangle, and a negative value indicated an upward direction of the hyoid triangle
H-PNS The distance between hyoid bone and PNS point Hyoid bone position in relation to the maxilla
H–H The perpendicular distance running from hyoid bone to a vertical line extending from the Sella point Horizontal position of hyoid bone
H-V The perpendicular distance running from hyoid bone to a horizontal line extending from the Sella point Vertical position of hyoid bone
  1. H, the most superior point of hyoid bone; Me, Menton; EB, epiglottis base; C3, the most supero-anterior point of the 3rd cervical vertebrae; PNS, posterior nasal spine; S, Sella