Research Article

Hyoid Bone Position in Patients with and without Temporomandibular Joint Osteoarthrosis: A Cone-Beam Computed Tomography and Cephalometric Analysis

Table 1

Hyoid and craniofacial measurements from cephalograms in this study.

MeasurementsDefinition

Hyoid measurements
Hy-Ba (mm)The distance between Hy point and Basion.
Hy to SN (mm)The distance between the Hy point and the sella-nasion (SN) plane on a line perpendicular to the SN plane through the Hy point.
Hy to FH (mm)The distance between the Hy point and the Frankfort horizontal (FH) plane on a line perpendicular to the FH plane through the Hy point.
Hy to PP (mm)The distance between the Hy point and the palatal plane (PP) on a line perpendicular to the palatal plane through the Hy point.
Hy to MP (mm)The distance between the Hy point and the mandibular plane (MP) on a line perpendicular to the MP plane through the Hy point. If the Hy point is inferior to the MP plane, the measurement is positive.
Hy-RGn (mm)The distance between Hy point and RGn point.
Hy-C3 (mm)The distance between Hy point and C3 point.
Hy to C3-RGn (mm)The distance between the Hy point and the line formed by the C3 and RGn point on a line perpendicular to the C3-RGn line. If the Hy point is inferior to the C3-RGn line, the measurement is positive.
C3-RGN (mm)The distance between C3 point and RGn point.
Go-Hy-MeAngle formed by the Gonion-Hy line and the Hy-Menton line.
Hy-S (mm)The distance between Hy point and sella.
Hy-C3-S (°)Angle formed by the Hy-C3 line and the C3-sella line.
C3-Hy-S (°)Angle formed by the Hy-C3 line and the Hy-sella line.

Craniofacial measurements
SNA (°)Angle between the SN plane and the nasion-A point line.
SNB (°)Angle between the SN plane and the nasion-B point line.
ANB (°)Angle between the nasion-A point line and the nasion-B point line.
Wits (mm)The distance between vertical lines from A point and B point to the occlusal plane.
FMA (°)Frankfurt-mandibular plane, formed by the mandibular plane and the FH angle.
FH-OP (°)Angle formed by the occlusal plane and the FH angle.
Saddle angle (°)Angle formed by the SN plane and the S-Ar line.
Articular angle (°)Angle formed by the S-Ar line and the Ar-Go line.
Gonial angle (°)Angle formed by the Ar-Go line and the mandibular plane.
Interincisal angle (°)Angle formed the long axis of the upper incisor and low incisor.
Ramus height (mm)Ar-Go, the distance between articulare and gonion.
Mandibular body length (mm)Go-Me, the distance between gonion and menton.
Anterior cranial base length (mm)S-N, the distance between sella and nasion.
Posterior cranial base length (mm)S-Ar, the distance between sella and articulare.
Anterior facial height (mm)N-Me, the distance between nasion and menton.
Posterior facial height (mm)S-Go, the distance between sella and gonion.
Overjet (mm)The horizontal distance between the upper and lower incisal edge with reference to the occlusal plane.
Overbite (mm)The vertical overlap between the upper and lower incisal edge.