Which of the following veins is most commonly used for venipuncture?

The median cubital vein is the most commonly used vein for venipuncture due to its prominent location and accessibility. It is situated in the antecubital fossa, the area in front of the elbow, making it easy to locate and puncture. This vein is generally larger than the other veins in this area, which helps to facilitate the withdrawal of blood and decreases the chances of complications during the procedure.

Additionally, because the median cubital vein typically has a relatively fixed position and is centrally located between the two main arteries of the arm (the cephalic and basilic veins), it allows for a safe and effective approach to drawing blood. Moreover, using this vein is generally less painful and has a lower risk of accidentally hitting nearby nerves compared to other veins in the arm.

In clinical practice, the median cubital vein is often the preferred choice of healthcare professionals for routine blood sampling and intravenous access, primarily because of these advantageous characteristics.