The Popeye sign: beyond the bulge-a proposal for a standardized definition and classification.

The Popeye sign is a classic eponym describing the cosmetic deformity following long head of the biceps tendon (LHBT) retraction. While frequently cited, its diagnosis remains subjective and standardized criteria are lacking. Muscle mass, body mass index, and surgical treatment of LHBT pathology as well as patient perceptions can all influence the prevalence and functional effect of the Popeye sign. This article reviews the historical origin of the eponym and its clinical relevance. Furthermore, we propose a novel, standardized diagnostic grading system to quantify the Popeye sign, facilitating more consistent reporting in future clinical research.