Background: There is an opinion that improper postures of the head and cervical spine are associated with temporomandibular joint (TMJ) disorders (TMDs).
Objects: The aim of this study was to investigate the proportions among the cervical kyphotic angle, physical symptoms including the pain intensity level of the TMJ, and severity of TMD disability in patients diagnosed with TMD.
Methods: Sixty-two subjects participated in the study. The evaluation tools included measurements of the cervical kyphotic angle based on the Ishihara index, pressure pain threshold (PPT) on the TMJ, maximal mouth opening (MMO) without pain, current pain intensity level of the TMJ measured using the Quadruple Visual Analogue Scale (QVAS), Korean TMD (KTMD) disability index, KTMD Symptom Frequency/Intensity Scales (SFS/SIS), and Korean Headache Impact Test-6. Correlation analysis was conducted to investigate the correlations between the cervical kyphotic angle and parameters related to TMJ symptoms.
Results: Variables that were significantly correlated with the cervical kyphotic angle were the PPT around the TMJ (r = 0.259, p < 0.05), current pain intensity level of the TMJ based on the QVAS (r = –0.601, p< 0.01), and usual pain intensity level based on the SIS (r = –0.379, p < 0.01). The level of TMD functional disability was significantly correlated with the degree of headache (r = 0.551, p < 0.01), level of PPT of the TMJ (r = –0.383, p < 0.01), pain-free MMO (r = –0.515, p < 0.01), pain intensity level of the TMJ based on the QVAS (r = 0.393, p < 0.01), TMD symptom frequency (r = 0.739, p < 0.01), usual pain intensity of the TMJ (r = 0.624, p < 0.01), and most severe pain intensity of the TMJ (r = 0.757, p < 0.01).
Conclusion: There is a positive correlation between the cervical kyphotic angle and PPT and a negative correlation between the current and usual pain intensity levels of the TMJ. The cervical kyphotic angle was a predictor of the pain level, tenderness threshold, and intensity of pain in the TMJ.

INTRODUCTION
MATERIALS AND METHODS
    1. 연구대상자
    2. 연구의 절차
    3. 평가방법 및 측정도구
    4. 분석방법
RESULTS
    1. 연구대상자의 일반적 특성
    2. 목뼈의 뒤굽음 각 정도와 통증 수준 및 턱관절 기능장애 관련변수 간에 상관관계
    3. 목뼈 뒤굽음 각에 영향을 미치는 요인에 대한 회귀분석
DISCUSSION
CONCLUSIONS
REFERENCES

• 이인수(대전대학교 보건의료대학원 물리치료학과) | In-su Lee (Department of Physical Therapy, Graduate School of Health and Medicine, Daejeon University)
• 김선엽(대전대학교 보건의료과학대학 물리치료학과) | Suhn-yeop Kim (Department of Physical Therapy, College of Health and Medical Science, Daejeon University) Corresponding Author