Temizsoy Korkmaz, FulyaCoşkun, OsmanGürses, İlke AliGayretli, ÖzcanÖzdemir, SevimÖztürk, AdnanKale, Ayşin2025-11-202025-11-202025Temizsoy Korkmaz, F., Coşkun, O., Gürses, İ. A., Gayretli, Ö., Özdemir, S., Öztürk, A., & Kale, A. (2025). Origin-order classification of axillary third-part branching: Donor-based dissection–CTA correlation for surgical planning. Bratislava Medical Journal, https://doi.org/10.1007/s44411-025-00393-11336-0345https://doi.org/10.1007/s44411-025-00393-1https://hdl.handle.net/20.500.13055/1191Purpose Variations in the branching of the subscapular artery (SSA), anterior circumflex humeral artery (ACHA), and posterior circumflex humeral artery (PCHA) are directly relevant to reconstructive planning with subscapular-system flaps and to humeral-head perfusion in shoulder surgery. Evidence organized around an origin-order–based framework remains limited. We aimed to address this gap by comparing body-donor dissections and computed tomography angiography (CTA) to provide a clinically useful classification and morphometric reference. Methods We performed a two-arm cross-sectional morphometric study: body-donor dissection (28 donors; bilateral, 56 sides) and CTA (25 patients; bilateral, 50 sides). In total, 104 sides were evaluated; 96 were classifiable. Classification used the sequential SSA–ACHA–PCHA origin order and common-trunk presence. Ostial diameters and SSA → CSA distances were measured; the radial nerve (NR)–SSA relationship was assessed in donors. origin_order__five_type_classif… Results In donors, Type-1, -2, -3, and -4 accounted for 36.5%, 32.7%, 23.1%, and 7.7%, respectively; Type-5 was absent. In CTA, Type-1, -4, and -5 comprised 93.2%, 2.3%, and 4.5% (one bilateral case); Types-2/-3 were not observed. Inter-modality comparison showed a longer SSA → CSA distance and smaller TDA/CSA diameters in CTA (all p < 0.001), while the SSA ostial diameter was similar. A posterior NR course relative to the SSA was associated with a longer SSA → CSA distance (p = 0.026). Conclusion An origin-order–based classification, corroborated across dissection and CTA, yields a practical map for (i) single-pedicle harvesting within the subscapular system and chimeric flap design, and (ii) avoiding iatrogenic compromise of humeral-head vascularity during shoulder procedures. Incorporating presurgical CTA mapping of the SSA and its branches may enhance safety where variants (e.g., short/combined trunks, rare Type-5) are suspected.eninfo:eu-repo/semantics/closedAccessAxillary ArterySubscapular Artery (SSA)Anterior Circumflex Humeral Artery (ACHA)Posterior Circumflex Humeral Artery (PCHA)Computed Tomography Angiography (CTA)Body-Donor DissectionReconstructive SurgeryShoulder SurgeryArticle10.1007/s44411-025-00393-1Q2Q2