Analysis of the Intramuscular Innervation of the Lateral Pterygoid Muscle

Abstract

The lateral pterygoid muscle has unique anatomical, physiological and functional properties. Since it is attached to the temporomandibular joint (TMJ) disc, its pathologies are closely related to TMJ disorders, which affect many people worldwide. Muscle structures and units are characterized by their morphological appearance, nerve distribution and function. In the present study, we examined the intramuscular innervation pattern of the lateral pterygoid muscle using modified sihler's method. Two types of innervation pattern were evident. In type I, representing the majority of the samples, a total of three branches arising from the main trunk of the mandibular nerve and the buccal nerve innervated the inferior head of the muscle, while branches from the buccal nerve innervated the superior head. In type II, divisions of the lateral pterygoid nerve branched from the buccal nerve located between the heads of the lateral pterygoid muscle and innervated each head separately. Interestingly, muscle bundles with a stronger tendineous structure showed much more innervation than other parts of the muscle. Future studies including quantitative analysis of the nerve distribution to the muscle bundles are warranted.

The morphological variations of the lateral pterygoid muscle: A systematic review

“…Sugisaki et al (1986), Naohara (1989), Wilkinson (1988), Abe et al (1993), Petermann (1994) and Akita et al (2003) did not note facts about age distribution of their examined subjects. Foucart et al (1998), Fujita et al (2001), Akita et al (2003) and Abe et al (2011) gave information about the gender distribution but did not identify a correlation between gender distribution and morphology of the LPM.…”

“…2). 11 studies took into account that the LPM may have variations and also considered the relative frequency of each variation (Sugisaki et al, 1986;Naohara, 1989;Wilkinson and Chan, 1989;Abe et al, 1993;Petermann, 1994;Foucart et al, 1998;Fujita et al, 2001;Akita et al, 2003;Pompei Filho et al, 2009;Kiliç et al, 2010;Abe et al, 2011). Sugisaki et al (1986), Naohara (1989), Abe et al (1993), Foucart et al (1998) showed that LPMs may have one, two or three heads.…”

“…MAE: meatus acusticus externus; MAI: meatus acusticus internus; FO: foramen ovale; A: anterior; P: posterior. Fujita et al, 2001;Akita et al, 2003;Pompei Filho et al, 2009;Kiliç et al, 2010;Abe et al, 2011), because some of these authors examined their subjects from different planes and perspectives. The authors depicted the frequency of each anatomical variation of the LPM.…”