The internist’s vein

The internist’s vein

In the complex multi-­‐disciplinary hospital systems of today, it is rare for physicians to perform blood draws on their patients. In a low resource setting, however, phlebotomy is an exceptionally useful skill for physicians to master. Moreover, there are times when a physician may be called to attempt a blood draw when a phlebotomist or nurse has been unsuccessful.

The search for a “good vein” is often haphazard. The antecubital fossa, forearm, and dorsa of the hand and foot are typically explored. While performing blood draws at the Pacific Free Clinic, I have found the distal cephalic vein to be an excellent (and often overlooked) target for phlebotomy. In the past, this vein has been referred to as the internist’s vein. Folklore suggests that this vein was often used by the busy internist who quickly needed a blood sample and did not have time to go searching for veins.

The internist’s vein runs between the tendons of the extensor pollicis brevis and the extensor pollicis longus. When the thumb is abducted, these tendons protrude, creating a landmark known as the anatomical snuff box. I have found the internist’s vein to be especially useful in patients who are “difficult sticks.” The utility of this vein is two-­‐fold. First, although the anatomy of superficial veins can be quite variable, this vein is nearly always present. Second, the internist’s vein tends to be larger and less mobile than hand veins.

To draw blood from the internist’s vein, first identify the anatomical snuff box. Place a tourniquet around the distal forearm. Have the patient relax, and passively adduct (ulnar deviate) the patient’s wrist. In this position, you will typically see the vein coursing beneath the skin. Even if you cannot visualize the vein, you can trace its path by palpating along the anatomical snuff box.