Dysphagia

, Volume 7, Issue 4, pp 187–200

Coordination of mastication and swallowing

  • Jeffrey B. Palmer
  • Nathan J. Rudin
  • Gustavo Lara
  • Alfred W. Crompton
Article

DOI: 10.1007/BF02493469

Cite this article as:
Palmer, J.B., Rudin, N.J., Lara, G. et al. Dysphagia (1992) 7: 187. doi:10.1007/BF02493469

Abstract

The coordination of mastication, oral transport, and swallowing was examined during intake of solids and liquids in four normal subjects. Videofluorography (VFG) and electromyography (EMG) were recorded simultaneously while subjects consumed barium-impregnated foods. Intramuscular electrodes were inserted in the masseter, suprahyoid, and infrahyoid muscles. Ninety-four swallows were analyzed frame-by-frame for timing of bolus transport, swallowing, and phases of the masticatory gape cycle. Barium entered the pharynx a mean of 1.1 s (range −0.3 to 6.4 s) before swallow onset. This interval varied significantly among foods and was shortest for liquids. A bolus of food reached the valleculae prior to swallow onset in 37% of sequences, but most of the food was in the oral cavity at the onset of swallowing. Nearly all swallows started during the intercuspal (minimum gape) phase of the masticatory cycle. Selected sequences were analyzed further by computer, using an analog-to-digital convertor (for EMG) and frame grabber (for VFG). When subjects chewed solid food, there were loosely linked cycles of jaw and hyoid motion. A preswallow bolus of chewed food was transported from the oral cavity to the oropharynx by protraction (movement forward and upward) of the tongue and hyoid bone. The tongue compressed the food against the palate and squeezed a portion into the pharynx one or more cycles prior to swallowing. This protraction was produced by contraction of the geniohyoid and anterior digastric muscles, and occurred during the intercuspal (minimum gape) and opening phases of the masticatory cycle. The mechanism of preswallow transport was highly similar to the oral phase of swallowing. Alternation of jaw adductor and abductor activity during mastication provided a framework for integration of chewing, transport, and swallowing.

Key words

DeglutitionMasticationPhysicologyOral cavityPharynxDeglutition disorders

Copyright information

© Springer-Verlag New York Inc 1992

Authors and Affiliations

  • Jeffrey B. Palmer
    • 1
    • 2
    • 3
    • 4
  • Nathan J. Rudin
    • 1
    • 2
    • 3
  • Gustavo Lara
    • 4
  • Alfred W. Crompton
    • 4
  1. 1.Department of Rehabilitation Medicine, the Swallowing CenterJohns Hopkins UniversityBaltimoreUSA
  2. 2.Department of Otolaryngology-Head and Neck SurgeryJohns Hopkins UniversityBaltimoreUSA
  3. 3.Good Samaritan HospitalBaltimoreUSA
  4. 4.Museum of Comparative ZoologyHarvard UniversityCambridgeUSA
  5. 5.BaltimoreUSA
  6. 6.Francis Scott Key Medical CenterBaltimoreUSA
  7. 7.Harvard Medical SchoolBostonUSA