Validity of palpatory methods for locating structures in the masseteric and cervical regions using radiological images of the skull and cervical spine

Abstract

Introduction: The accuracy of palpation methods has been addressed by validity studies that compared their results with an imaging reference standard. Notwithstanding, many palpation methods still lack such validity and/or reliability analysis. Today, there is no evidence about the reliability and validity of most palpatory tests for the cervical spine. In addition, there is no consensus about the influence of personal and anthropometric data in their validity. Objective: This study aimed to examine the accuracy of palpation methods for locating the transverse processes of C1 (C1TP) and masseter muscle using radiologic images as the gold-standard method and the association between personal characteristics with the observed accuracy. Methods: Single-blinded, diagnostic accuracy study. Ninety-five participants (49 women, 58 ± 16 years of age) were enrolled in this study. A single examiner palpated the neck and face region of all participants to identify the C1TP and masseter muscles bilaterally. In sequence, participants underwent a multi-slice CT scan for assessment of the superimposed inner body structure. Two radiologists assessed the CT images using the same criteria and were both blinded regarding each other’s assessment and the anatomical landmarks under investigation. The palpation accuracy was calculated as the proportion of the correctly identified landmarks in the studied sample. The correlation of the palpation outcome (correct=1; incorrect=0) with age, sex (male=1; female=0), and body mass index was
investigated using the point-biserial correlation coefficient. Results: The right and left transverse processes were correctly located in 76 (80%, IC 95% 71-87) and 81 (85%, IC 95% 77-91 of the participants, respectively, and bilaterally in 157 events (83%, IC 95% 77-87) as evaluated by the agreement of the two radiologists. The masseter muscles were correctly localized bilaterally in 95/95 (100%) of the
participants. All demographic variables showed weak or lower point estimates of correlation with the accurate location of C1TP; only body mass was positively correlated to the correct location of C1TP at the right side (0.219, 95%CI 0.018 to 0.403, p = 0.033), determining ~5% of the variability of the accuracy. Conclusion: The accuracy of locating the C1 spinous processes and masseter muscles are high.