A new origin-based classification of the obturator artery with internal iliac wall mapping and morphometric analysis

The obturator artery shows substantial variation in its origin and early course, but heterogeneous classification schemes and non-standardised morphometry hinder comparison between anatomical and imaging studies. This cadaveric study aimed to provide a unified, origin-based classification of the obturator artery, to map its wall surface of origin on the arterial source vessel and to quantify its morphometry by side and sex. A total of 120 adult hemipelves were dissected using a standardised protocol, tracing the obturator artery from its origin on the iliac axis to the level of the obturator foramen. For each specimen, we recorded the arterial source vessel and, where applicable, the division of origin, the wall surface of origin on the arterial source vessel, and obtained length and external diameters at the origin and at the level of the obturator foramen. Four reproducible patterns were identified: Type I, a solitary branch from the anterior division of the internal iliac artery (53.4%); Type II, a common trunk with the internal pudendal artery (10.0%); Type III, a solitary branch from the posterior division (25.8%); and Type IV, a common trunk with the inferior epigastric artery from the external iliac artery (10.8%). Origins were predominantly from the anterior and anteromedial surfaces of the arterial source vessel, with no side- or sex-related differences in type or surface distribution. Mean length was approximately 67 mm, with diameters of about 2.4 mm at origin and 2.2 mm at the obturator foramen; calibre was greater in males, but morphometry did not differ across Types I–IV or surfaces of origin, and diameter showed near-linear preservation along the pelvic segment. This four-type, wall-referenced framework provides a pragmatic template to harmonise cadaveric and imaging reports and to support variant-aware planning of pelvic surgery and endovascular interventions.