Kinematic Relationship Between Temporomandibular and Cervical Spine Joints

The temporomandibular joints (TMJs) and the cervical spine exhibit a complex functional relationship due to their anatomical and biomechanical connections. Understanding how the mobility of these structures is assessed is important for comprehending their potential interplay in musculoskeletal disorders of the head and neck.

To synthesize and compare the methodologies and findings of studies that simultaneously assessed the mobility of both the TMJs and the cervical spine.

A comprehensive search of databases was conducted to identify relevant studies. The analysis included 15 studies that objectively analyzed movements of both the TMJs and the cervical spine. The methods used for assessing TMJ and cervical spine mobility were extracted and compared.

The most commonly used methods for assessing TMJ mobility were rulers or calipers for linear measurements, along with the TheraBite or Cranio-Mandibular Scale. The Zebris digital axiograph was the least frequently used. For cervical spine movements, the cervical range of motion or an inclinometer was most often used. In assessing TMJ mobility, maximal mouth opening (MMO) was consistently examined, while other movements were assessed less frequently. In assessing cervical spine mobility, flexion and extension were most often examined, followed by rotation and lateral flexion in some studies, with flexion and extension of the upper cervical spine being the least frequently assessed. Notably, no study examined TMJ mobility in different head positions relative to the body in the frontal plane (i.e., during lateral flexion of the cervical spine). None of the analyzed studies considered age and sex differences. The methodological heterogeneity of the studies made it difficult to draw unambiguous conclusions. The diversity of tools and protocols used made it difficult to compare results among studies.

Further research is needed to better understand the kinematic relationship between the TMJs and the cervical spine and to develop standardized assessment protocols. The methodological inconsistencies across existing studies highlight the need for more uniform approaches in future investigations.