Unusual variability of the superficial venous system of the upper limb and its consequences for deep venous system.

In our report we would like to present a variation of the two main superficial veins of the upper limb. In 21 (88%) explored upper limbs, the venous system showed a pattern similar to that presented in the anatomical textbook. However, in 4 (12%) others venous patterns differed from those already described. Especially in one of them the variant of the veins of the upper limb distinctly contrasted with the others. In that case, the basilic and cephalic vein, instead of the normal course to the arm where they should bypass the elbow pit, unexpectedly merged into one and formed one of the two brachial veins. Towards the axillary cavity it ran laterally over the entire arm regardless of the second brachial vein. In the armpit cavity, instead of connecting with the second one, it gave rise to an independent second vein - the accessory axillary vein. This uniqueness was based on that, independently from deep venous system, the superficial one formed their own net. The accessory axillary vein and the second brachial vein were completely formed by two main superficial veins: the basilic and cephalic vein. By describing this case we wanted to emphasize that in any surgical procedure on the upper limbs, especially on the venous system, there is a certain probability of encountering this anatomical variation. Another conclusion is that the catalogue of patterns of the venous system of the upper limb seems to be endless.