title: The human lateral pterygoid muscle.
abstract: One of the jaw muscles particularly implicated in temporomandibular disorders (TMD), a common form of non-dental chronic orofacial pain, is the human lateral pterygoid muscle. The precise role of this muscle in TMD is unclear as is the nature of the interaction between pain and motor function particularly involving this muscle. This research group has adopted a two-stage approach to studying the effects of pain on motor function. The first is to study normal orofacial motor function through recordings of jaw movement and electromyographic (EMG) activity from a number of jaw muscles (including recordings from the lateral pterygoid muscle; verification of electrode location achieved through computer tomography imaging) during a number of standardised jaw movements. These studies have defined the detailed functional properties of, in particular, the lateral pterygoid muscle, whose physiology and function is not well understood. In summary, the data are consistent with the hypothesis previously proposed that the lateral pterygoid should be regarded as a system of fibres that acts as one muscle, with varying amounts of evenly graded activity throughout its entire range, and with the distribution of activity within the muscle being determined by the biomechanical demands of the task. Our second approach has been to study the effects of experimental masseter muscle pain on the detailed functional properties (e.g., root-mean-square EMG activity) of the jaw muscles, especially the lateral pterygoid muscle. Preliminary data from these pain studies point towards significant effects of human experimental muscle pain on jaw muscle activity and jaw movement.
authors.affiliation: Jaw Function and Orofacial Pain Research Unit, Faculty of Dentistry, University of Sydney, Level 3, Westmead Centre for Oral Health, Westmead Hospital, Westmead, NSW 2145, Australia. gregm@usyd.edu.au
authors.forename: Greg M
authors.initials: GM
authors.lastname: Murray
authors.forename: Manish
authors.initials: M
authors.lastname: Bhutada
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Peck
authors.forename: Intira
authors.initials: I
authors.lastname: Phanachet
authors.forename: Daraporn
authors.initials: D
authors.lastname: Sae-Lee
authors.forename: Terry
authors.initials: T
authors.lastname: Whittle
mesh_terms: D004576:Electromyography; D006801:Humans; D008409:Mastication / Q000502:physiology; D009043:Motor Activity; D010146:Pain; D011626:Pterygoid Muscles / Q000503:physiopathology*; D013704:Temporomandibular Joint / Q000503:physiopathology; D013705:Temporomandibular Joint Disorders / Q000503:physiopathology*