Anatomical Architecture of the Adductor Magnus: A Cadaveric Study With Clinical Implications for Imaging-Based...

The adductor magnus (AM) is the largest muscle of the medial thigh compartment. Yet, detailed descriptions of its anatomical subdivisions and tendinous architecture remain incomplete, limiting accurate localization of muscle injuries on clinical imaging. This study systematically characterized the anatomical structure and morphological variations of the AM by dissecting nine AMs from nine formalin-embalmed Japanese donors. The AM was consistently divided into four distinct components based on insertion sites, fascicular architecture, and innervation: adductor minimus (APm), superior part of the adductor part (APs), inferior part of the adductor part (APi), and hamstring part (HP). Contrary to conventional descriptions stating that the entire adductor part inserts onto the medial lip of the linea aspera, the present study revealed that the APm and APs inserted onto the lateral lip, whereas only the APi attached to the medial lip and the medial supracondylar line. Multiple tendinous structures were systematically identified, including superficial and deep membranous origin tendons, insertion tendons, and intramuscular tendinous arches, with considerable interindividual variation in their morphology and position. These findings provide additional anatomical detail that may improve imaging-based localization of AM injuries and potentially reduce diagnostic errors, particularly in distinguishing AM injuries from those of semimembranosus origin. Further studies correlating these anatomical findings with clinical imaging are warranted to validate their clinical applicability.