Median cubital vein

In human anatomy, the median cubital vein (or median basilic vein) is a superficial vein of the arm on the anterior aspect of the elbow. It classically connects the cephalic vein and the basilic vein.

It is routinely used for venipuncture (taking blood) and as a site for an intravenous cannula. This is due to its particularly wide lumen, and its tendency to remain stationary upon needle insertion.

Structure
The median cubital vein is a superficial vein of the arm. It lies on the anterior aspect of the elbow, in the cubital fossa superficial to the bicipital aponeurosis. It bridges the cephalic vein and the basilic vein.

The median cubital vein receives a number of tributaries from the anterior forearm. The median antebrachial vein may or may not drain into the median cubital vein.

The median cubital vein issues a branch - the deep median vein - which pierces the fascial roof of the cubital fossa to join the brachial veins.

Variations
The arrangement of the basilic, cephalic, median cubital, and median antebrachial veins exhibits a wide range of variations. Classically, the median cubital vein bridges the cephalic and basilic veins across the midline to form a H-pattern. However, in many cases, the median cubial vein is absent, instead replaced by a dominant median antebrachial vein that splits into intermediate cephalic and basilic veins to drain in the cephalic and basilic veins, respectively, forming a M-pattern. A number of other patterns exist, including ones where no anastomosis occurs between the basilic and cephalic veins, and ones where the median cubital vein is doubled. When the median cubital vein is large, it transfers most or all blood from the cephalic vein to the basilic vein, so that the cephalic vein is either significantly diminished or altogether absent.

Clinical significance
The median cubital vein becomes prominent when pressure is applied to upstream veins as venous blood builds up.

The median cubital vein is routinely used for venipuncture (taking blood) and as a site for an intravenous cannula. This is due to its particularly wide lumen, and its tendency to remain stationary upon needle insertion. It becomes prominent when pressure is applied upstream, which makes needle insertion easier. Such pressure is created using a tourniquet.