An update on trismus: etiology, diagnosis and treatment

Trismus, or “lockjaw,” is a condition characterised by limited mouth opening due to masticatory muscle dysfunction. Its multifactorial etiology includes neurological and non-neurological causes, but current clinical guidance is fragmented. This narrative review synthesises current evidence on trismus pathophysiology, diagnosis, and treatment. We propose a novel etiological classification distinguishing neurological from non-neurological causes and introduce a stepwise diagnostic and management algorithm. The algorithm prioritises red flag conditions, guides differential diagnosis, and supports treatment decisions in both outpatient and hospital settings. By providing a structured framework, this review aims to facilitate early recognition of the conditions, inform targeted therapeutic strategies, and improve patient outcomes.