[A cinefluorographic study of hyoid bone movement during deglutition]

A quantitative study was performed to analyze movement of the hyoid bone on swallowing in 71 patients with pharyngo-laryngeal neurosis (44 males, 27 females), who had no abnormal findings either morphologically or functionally. The lateral X-ray cine (30 frames/sec) was taken while the patients swallowed the contrast medium in the upright position, and precise movement of the hyoid bone was examined using a motion analyzer. The movement was divided into 5 phases; initial slow elevation from the resting position (1st elevation phase), then a quick upwards shift to the highest position (2nd elevation phase), where the hyoid bone remained temporarily (static phase), followed by rapid and slow descending shifts towards the resting position (1st and 2nd descending phase, respectively). The resting position of the hyoid bone is significantly lower in males than in females and it seemed to get lower with age in both sex. When compared to the younger group (age 10-30), the older group (age 60-70) had significantly more distance and longer duration of deglutition in the 1st elevation phase, whereas the 2nd elevation phase did not differ among the age group. The results of this study indicate that prolongation of the time and distance of the 1st elevation phase are more significant in the older group, which may well explain the cause of delayed of deglutition.