External jugular cannulation is a vascular access option that allows for relatively large bore devices and the delivery of larger volumes of fluid than might otherwise be possible through a peripheral vein.
The external jugular vein is formed below the ear and behind the angle of the mandible, where a branch of the posterior facial vein joins the posterior auricular vein. The external jugular vein then passes downward, and obliquely backward, across the surface of the sternomastoid muscle before piercing the deep fascia of the neck just above the middle of the clavicle, ending in the subclavian vein lateral to the anterior scalene muscle. Valves are present in this vein at the entrance to the subclavian vein and about four centimeters above the clavicle.