The never-ending confusion between subclavian vein and axillary vein.

The use of precise and unequivocal terminology is crucial in clinical and scientific communication. A frequent source of error involves the anatomical confusion between the axillary vein and the subclavian vein. Anatomically, the transition from the axillary vein to the subclavian vein occurs at the lateral border of the first rib, beneath the clavicle. Consequently, the vessel typically visualized by ultrasound in the infraclavicular region is the axillary vein, not the subclavian vein. Nevertheless, numerous international guidelines and clinical studies continue to misidentify the thoracic segment of the axillary vein as the "subclavian vein." This persistent mislabeling hinders the international standardization of ultrasound-guided procedures, complicates the comparison of various techniques, and-most importantly-risks misinterpretation of evidence-based recommendations for clinical practice.