Mandibular movement and muscle activity during mastication in the guinea pig (Cavia porcellus)

Research output: Contribution to journalArticle

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Abstract

Optoelectronic analysis of mandibular movement and electromyography (EMG) of masticatory muscles in Cavia porcellus indicate bilateral, unilateral, and gnawing cycles. During bilateral and unilateral cycles, the mandibular tip moves forward, lateral, and down during the lingual phase of the power stroke to bring the teeth into occlusion. EMG activity is generally asymmetric, with the exception of activity of the temporalis muscle during bilateral cycles. During gnawing cycles, the mandible moves in an anteroposterior direction that is opposite that during bilateral and unilateral chew cycles. Bilateral and unilateral cycles of pellets were significantly longer than carrot. With the exception of the width of bilateral cycles, the magnitude of cycle width, length, and height during the mastication of carrots was greater than that during the mastication of pellets. Significant differences exist between EMG durations during mastication of pellets and carrots. The lateral pterygoid displays continuous activity during gnawing cycles. Significant differences also exist in the durations of EMG activity between the working and balancing side during all three cycle types. High level activity of balancing side temporalis and anterior belly of digastric (ABD) during bilateral cycles occurs during rotation and depression of the mandible during the power stroke. The temporalis apparently provides a 'braking' or compensatory role during closing and power strokes. Differences between Cavia masticatory patterns and those shown by Rattus and Mesocricetus are apparently due to differences in dental morphology, occlusal relationships, and, possibly, the poorly developed temporalis in Cavia. The large number and wide diversity of rodent groups afford students of mammalian mastication an opportunity to investigate and compare different masticatory specializations.

Original languageEnglish (US)
Pages (from-to)147-169
Number of pages23
JournalJournal of Morphology
Volume170
Issue number2
StatePublished - 1981
Externally publishedYes

Fingerprint

electromyography
Mastication
Electromyography
mastication
guinea pigs
Daucus carota
Guinea Pigs
Cavia
stroke
carrots
pellets
Muscles
muscles
Stroke
Mandible
Tooth
teeth
Mesocricetus
Masticatory Muscles
Rattus

ASJC Scopus subject areas

  • Agricultural and Biological Sciences (miscellaneous)
  • Developmental Biology
  • Anatomy

Cite this

Mandibular movement and muscle activity during mastication in the guinea pig (Cavia porcellus). / Byrd, Kenneth.

In: Journal of Morphology, Vol. 170, No. 2, 1981, p. 147-169.

Research output: Contribution to journalArticle

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