Background: Surgical procedures such as thenar flaps and radial artery (RA) harvesting call for an elaborate anatomical study of the RA's superficial palmar branch (SPB). The aim of this study was to describe the branching pattern of this vessel related to the morphometric characteristics and variations of this artery. Materials and methods: Twenty 4% formalin solution injected hands were dissected. For the morphometric study we used another group of thirty five human hands of adult persons, injected with methylmethacrylate fluid into the ulnar and radial arteries. As soon as polymerization was completed, a 40% solution of potassium hydroxide was applied for corrosion. The vascular arterial casts were examined under the stereoscopic microscope and precise drawings of each specimen were made. Results: In the majority of cases (75%) SPB passed superficially, over the abductor pollicis brevis muscle. The mean diameter of the SPB, very variable depending on its length and field of supply, was 1.52±0.49 mm, ranging from 0.8 to 2.7 mm. Developed SPB type, was present in 31.4% of hands, with the diameter of 1.7 mm and larger (mean 1.95 mm), continuing distally to become the radialis indicis artery (RIA), with an average caliber of 1.2 mm, and with important branches to the thumb. In most hands, (68.6%), the hypoplastic SPB, was present, with a mean diameter of 1.17 mm, and the field of supply within the thenar area. Conclusions: Knowledge of the SPB dominance, and existence of anastomotic vessels in its field of supply are of importance to avoid the risk of possible ischemic sequelae in the hand associated with harvesting the RA.