Regional properties of the superior head of human lateral pterygoid muscle.

The aim of this study was to investigate functional heterogeneity within the superior head of the human lateral pterygoid (SHLP) muscle by comparing the functional properties (e.g. firing rates) of single motor units (SMUs) between different arbitrarily defined regions of the SHLP, namely, medial, middle or lateral; origin or insertion; and superior or inferior regions.

Activity of superior head of human lateral pterygoid increases with increases in contralateral and protrusive jaw displacement.

The hypothesis was that the superior head of human lateral pterygoid muscle (SHLP) plays a similar role in jaw movement as the inferior head of human lateral pterygoid muscle (IHLP). The aims were to determine the functional properties of SHLP single motor units (SMUs) and root mean square activity (RMS) of the SHLP during contralateral and protrusive jaw movement tasks and to compare these features with those identified previously for the IHLP. In 22 human subjects, SMUs were recorded intramuscularly from computer tomography-verified sites within the SHLP during standardized contralateral and protrusive jaw movement tasks recorded by a jaw-tracking device.

Threshold properties of single motor units in superior head of human lateral pterygoid muscle.

Unlabelled: The superior head of the human lateral pterygoid muscle (SHLP) may play a similar role in jaw movement as the inferior head (IHLP).

Objective: The aim was to determine whether threshold properties of single motor units (SMUs) within SHLP during jaw tasks were comparable to those identified for IHLP.

Design: In 24 human subjects, SMUs were recorded intramuscularly from computer-tomography verified sites within SHLP during standardised jaw tasks recorded by a jaw-tracking device.

The human lateral pterygoid muscle.

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.

Functions of the lateral pterygoid muscle.

The lateral pterygoid, a muscle of mastication has been implicated, with little evidence, in the aetiology of temporomandibular disorders. Three to five percent of the population in developed countries requires treatment for temporomandibular disorders. There is limited information about the normal function of the muscle, which is anatomically divided into a superior and an inferior head.