Müller's Muscles: Three Different Smooth Muscles of the Eye and Orbit

Purpose: The eponym “Müller’s muscle” has been used in various textbooks and academic articles to refer collectively to three different smooth muscles: orbital muscle, superior tarsal muscle and the circular fibers of the ciliary muscle. The aim of this review is to highlight the terminological confusion created in the literature by the use of the Müller’s muscle eponym as a common name for three different muscles associated with the eye and orbit. Methods: A comprehensive literature review was conducted in academic databases such as PubMed, Google Scholar, Scopus, and Web of Science to clarify clarify the appropriate usage of the term “Müller’s muscle”. Additionally, the descriptions of these muscles in leading medical school sources, atlases, and textbooks were examined. The detailed topographical locations, anatomical and morphological characteristics, histological structures, innervation and vascularisation, and clinical syndromes of the muscles were presented in a comparative manner. Conclusion: We believe that our study will contribute to preventing naming confusion regarding these muscles, collectively referred to as ‘Müller's muscle,’ in future anatomy atlases, clinical guidebooks, and scientific studies.