Enhancing morphological understanding of the lateral pterygoid muscle for orofacial pain treatment: a cadaveric study

Aims: Injections to the lateral pterygoid muscle (LPM) have gained popularity for managing orofacial pain. Techniques like ultrasonography (USG), electromyography (EMG), and arthroscopy help prevent improper injections and tissue trauma during the procedure, but they require practitioner expertise and experience. Arthroscopy, while precise, is invasive. Blind injections are simpler and convenient for outpatient settings, but their safety is debated. This study examines the anatomical traits of the area of the injection to contribute to the safety and efficacy of these injections for temporomandibular-related orofacial pain. Methods: The LPM consistently displayed two distinct bellies-superior and inferior-in 16 dissections of 8 cadavers. We measured lateral pterygoid plate (LPP) depth and length, pterygomaxillary angle, superior and inferior head vertical length, superior and inferior head thickness, distance between zygomatic arch and mandibular notch, and distance between superior border of inferior head and mandibular notch. Results: Significant correlations were found between distances, thicknesses, and lengths of the muscle heads, indicating critical anatomical relationships relevant for safe injections. The mean age of cadavers was found as 79.00±1.78 years (In this article, the ‘±’ notation corresponds to the standard deviation). The average depth and length of the LPP were 43.47±3.34 mm and 15.61±1.09 mm, respectively. The distance from the zygomatic arch to the mandibular notch was 10.76±0.39 mm, whereas the distance from the superior border of the inferior head to the mandibular notch was 6.74±0.29 mm. Significant associations were found between the distance from the zygomatic arch to the mandibular notch and both the thickness and length of the superior head (p=0.011 and p=0.005). Correlations were also observed between the distance from the superior border of the inferior head to the mandibular notch and the thickness of both heads (p