Positions and Movements of Mandible and Hyoid Bone During Swallowing

Abstract

The positions and movements of the mandible and the hyoid bone during swallowing with and without anaesthesia of the temporomandibular joint capsules were studied cineradio-graphically in 11 female subjects aged 19-31 years. Swallowing with contact between the teeth was found to be more common than swallowing without contact. The contact was established most often in the intercuspal position but contact occurred also anteriorly and posteriorly to the intercuspal position and in the retruded position of the mandible. No difference was found in the occurrence or localisation of the contact between the teeth on comparison between swallowing before and during the anaesthesia.

The pattern of movements of the hyoid bone were found to be regular in some persons with an even circular or elliptic path of movement during the act of swallowing, while in others the path was more irregular, sometimes with crossing pathways. The pattern of movement did not vary with the medium swallowed (saliva, watery barium and viscous barium). The pattern of movement was independent of the presence and localisation of contact between the teeth during swallowing and was not affected by temporomandibular joint anaesthesia.

Key Words:

• Cinefluorography
• Hyoid bone
• Deglutition
• Temporomandibular joint