Objective <p><?tk 2?>The widespread adoption of minimally invasive thoracic surgery necessitates precise anatomical knowledge; however, pulmonary morphology frequently deviates from textbook descriptions. We systematically investigated in vivo fissural variations and their relationships with vascular branching to guide contemporary operative strategies.</p> Methods <p><?tk 2?>We conducted a retrospective observational study of 209 patients who underwent anatomical lung resection (128 right-sided, 81 left-sided) with meticulous intraoperative exploration between 2002 and 2020. Fissural integrity was assessed using an adapted Craig classification and correlated with pulmonary artery branching patterns and patient demographics.</p> Results <p><?tk 2?>Anatomical variations were significantly more prevalent in the left lung (77.0%) than in the right lung (36.7%). Complete fissures were anatomically rare; the major fissure was incomplete in 80.5% of right lungs and 66.7% of left lungs. Furthermore, the right minor fissure was incomplete in 60.2% of cases. A significant correlation was identified between right major fissure completeness and superior segmental artery (A6) branching patterns (<i>p</i> = 0.007). Specifically, an incomplete right major fissure was uniformly associated with a single A6 branch (100%), whereas complete fissures demonstrated a single branch in 88.0% of cases and a double-branch pattern in 12.0%.</p> Conclusion <p><?tk 2?>Incomplete pulmonary fissures constitute the predominant anatomical norm rather than an anomaly. This high prevalence, coupled with complex vascular associations, undermines reliance on standard anatomical templates. Consequently, individualized operative planning—utilizing tailored approaches such as fissureless lobectomy techniques and advanced preoperative imaging—is imperative to mitigate complications.</p> Graphical abstract