Precise Dry Needle Insertion Point and Approach to the Lateral Pterygoid Muscle: A Cadaveric Study

Temporomandibular joint disorders are a common cause of chronic orofacial pain and often involve the lateral pterygoid muscle (LPM). However, dry needling is limited by poor palpation reliability and difficult-to-standardize intraoral or imaging guidance. This cadaveric study aimed to define an optimal extraoral insertion point, angle, and needle length for safely reaching the LPM. Methods: Sixteen adult cadaver heads (10 males, 6 females; 32 sides) were studied. Dissections performed on one side guided contralateral needling, assuming morphological symmetry. A safe insertion point 17 mm perpendicularly below 3/5 of the canthal-tragus line, with optimal angles of 15° and 90°, was identified. Anthropometric measurements and computed tomography confirmed needle length and angles. Results: Sex-related differences were found in anthropometric measurements, while no significant right–left differences were observed. At 15°, the median length to the LPM was 43.45 (41.24–46.03) mm in males and 40.93 (40.25–42.38) mm in females (p = 0.031); at 90°, 44.08 (42.66–45.48) mm in males and 39.95 (39.34–40.46) mm in females. At both angles, needle length differed significantly between sexes (p < 0.05), but not between sides (p > 0.05). Conclusion: From the specific insertion point determined in the study, the LPM can be reached at 15° and 90° angles, with median lengths of 43.45 (41.24–46.03) mm and 44.08 (42.66–45.48) mm for males, and 40.93 (40.25–42.38) mm and 39.95 (39.34–40.46) mm for females, respectively. We found that the LPM could be reached at the same angles but with different needle lengths between sexes.