Purpose: There have been several studies regarding the relationship between deglutition and the cervical spine; however, the movement of the cervical spine during deglutition has not been specifically studied. The purpose of the present study was to clarify how the cervical spine moves during normal deglutition.
Methods: We conducted videofluorography in 39 healthy individuals (23 men; 16 women; mean age, 34.3 years) with no evidence of cervical spine disease and analyzed images of the oral and pharyngeal phases of swallowing using an image analysis technique. Analyzed sections included the occiput (C0) and the first to seventh cervical vertebrae (C1-C7). The degrees of change in angle and position were quantified in the oral and pharyngeal phases.
Results: In the pharyngeal phase, C1, C2, and C3 were flexed (the angle change in C2 was the most significant with a mean flexion angle of 1.42°), while C5 and C6 were extended (the angle change in C5 was the most significant with a mean extension angle of 0.74°) in reference to the oral phase. Angle changes in C0, C4, and C7 were not statistically significant. C3, C4, C5, and C6 moved posteriorly (the movement in C4 was the most significant, mean = 1.04 mm). C1, C2, and C3 moved superiorly (the movement in C2 was the largest, mean = 0.55 mm), and C5 and C6 moved inferiorly. Movements in C0 and C7 were not statistically significant.
Conclusions: These findings suggest that the cervical spine moves to reduce physiological lordosis during deglutition.