Do Temporomandibular Disorder Patients with Joint Pain Exhibit Forward Head Posture? A Cephalometric Study

Table 1

Cephalometric parameters used in this study.

Cephalometric parameters	Definition
Ba-C3ia (mm)	The distance between basion and the most inferior-anterior point on the body of the third cervical vertebra. Higher values of Ba-C3ai represent more severe FHP.
C2ap-C4ip (mm)	The distance between the apex of the odontoid process of the second cervical vertebra and the most inferior-posterior point on the body of the fourth cervical vertebra (C4ip). C2ap-C4ip represents the length of the upper segment of the cervical column.
Cranio cervical angle (°)	The posterior-inferior angle of the intersection of the McGregor’s plane (MGP) and odontoid plane (OP). Higher values of cranio cervical angle represent a flexion position of the head and in an FHP position.
CVT/OPT (°)	The anterior-inferior angle between the posterior tangent to the odontoid process through C4ip (CVT) and the posterior tangent to the odontoid process through C2ip (OPT). Higher values of CVT/OPT represent a larger cervical curvature and more severe FHP.
CVT/FH (°)	The anterior-inferior angle between CVT and Frankfort horizontal line (FH). Higher values of CVT/FH represent more severe FHP.
CVT/NSL (°)	The anterior-inferior angle between a line that goes from the sella turcica to the nasion and the tangent that goes posterior to the odontoid process through the most posterior and inferior aspect of the fourth cervical vertebra body. Higher values of CVT/NSL represent more severe FHP.
CVT/RL (°)	The anterior-inferior angle between a tangent line to the posterior border of the mandibular ramus and the tangent that goes posterior to the odontoid process through the most posterior and inferior aspect of the fourth cervical vertebra body. Higher values of CVT/RL represent more severe FHP.
OPT/RL (°)	The anterior-inferior angle between a tangent line to the posterior border of the mandibular ramus and the tangent that goes posterior to the odontoid process through the most posterior and inferior aspect of the second cervical vertebra body. Higher values of OPT/RL represent more severe FHP.
NSL/C2’ (°)	The anterior-superior angle between a line that goes from the sella turcica to the nasion and the tangent line to the inferior edge of the second cervical vertebra. Higher values of NSL/C2’ represent increase in cervical forward flexion in the second cervical segment and more severe FHP.