Three-dimensional movement analysis of lateral pterygoid electromyographic activity during mastication in the rat

K. E. Byrd, Y. Chai

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


Simultaneous recordings of mandibular movement in three dimensions (frontal, horizontal and sagittal plane), and lateral pterygoid electromyographic (EMG) data during mastication of pellets and slurry, were collected from 5 rats by the opto-electronic mandibular tracking (OMT) method and computerized digital-processing of the EMG wave-forms. The microcomputer analyses allowed determination of frontal-, horizontal- and sagittal-plane movement displacements and velocities for whole chew cycles and, during lateral pterygoid activity, opening burst (OB) and closing burst (CB) latencies. There were significant (p ≤ 0.01) differences between duration, displacement and velocity data from slurry and pellet chew cycles. OB latencies were significantly (p ≤ 0.01) longer than CB, and OB displacements started significantly (p ≤ 0.01) farther from minimal gape than CB ones. Working-side OB activity occurred as the mandible moved inferiorly, laterally and posteriorly; working-side CB activity occurred as the mandible moved superiorly, medially and anteriorly. A secondary peak of OB activity, coinciding with anterior sagittal translation during the last third of mandibular depression, was detected; this may represent independent activity of the rat superior lateral pterygoid effecting anterior translation of the mandibular-joint disc and capsule. Rat lateral pterygoid activity has the same basic, bimodal pattern (active during both mandibular depression and elevation) as is found in humans.

Original languageEnglish (US)
Pages (from-to)635-640
Number of pages6
JournalArchives of Oral Biology
Issue number9
StatePublished - 1988
Externally publishedYes

ASJC Scopus subject areas

  • Otorhinolaryngology
  • Dentistry(all)
  • Cell Biology

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