<p>Pseudoankylosis of the temporomandibular joint (TMJ) is a rare condition causing restricted mandibular movement without true osseous fusion. This case report presents an 85-year-old woman with TMJ pseudoankylosis secondary to chronic inflammation, a unique etiology for pterygomandibular fusion. The patient exhibited limited mouth opening, swelling, and tenderness in the left facial region. Imaging revealed an enlarged left condyle and hypertrophic lateral pterygoid plate in close approximation, consistent with pterygomandibular impingement. Conservative management was chosen due to the patient’s age and comorbidities. This case contributes to the limited literature on pterygomandibular fusion and expands our understanding of TMJ pseudoankylosis in geriatric patients with chronic inflammation.</p>