Morphological Spectrum of the Lateral Pterygoid Muscle: Radioanatomical Analysis, Systematic Review, and...

Background and Objectives: The lateral pterygoid muscle (LPM) is typically described as a two-headed muscle within the infratemporal fossa. However, cadaveric and imaging studies have revealed substantial variability in the number of heads, insertion patterns, and relations to neurovascular structures. Materials and Methods: An observational study of 250 brain computed tomography angiographies (CTAs) was performed to assess LPM morphology. Additionally, a systematic review and meta-analysis were conducted in accordance with PRISMA 2020 and Evidence-based Anatomy guidelines. Pooled prevalence estimates were calculated with random-effects models. Results: The current study included 250 CTAs for the original study and 1702 muscles for the meta-analytic evidence. During the original study, the two-headed configuration was most common (74.4%), followed by three-headed (14%), one-headed (10.8%), and four-headed (0.8%) morphologies. Symmetry was observed in 75.2% of patients. Meta-analysis confirmed the predominance of the two-headed type (73.98%, 95% CI: 68.22-79.38), with three-headed (16.82%), one-headed (4.37%), and four-headed (<0.01%) variants occurring less frequently. Subgroup analyses showed no significant differences by study type or sample size, though European populations exhibited a higher prevalence of one-headed forms. Conclusions: The LPM demonstrates considerable morphological variability, extending beyond the traditional two-headed model. Recognition of these variants is essential for understanding temporomandibular joint function, interpreting imaging, and planning surgical or interventional procedures within the infratemporal fossa. Advanced imaging provides a reliable tool for individualized anatomical assessment, supporting safer clinical practice.