Ultrasonographic scans of the right side of the neck of 16 subjects were done in order to determine the anatomical features relevant to efficient cannulation of the internal jugular vein. The cross sectional area of the jugular vein was estimated from scans at the level of the cricoid as well as 1.5 cm cephalad and caudad to the cricoid; the jugular was significantly larger caudad to the cricoid. A head-down tilt of 14° provided significant distension of the jugular, similar to that produced by a Valsalva maneuver. Both palpation of the carotid and extreme rotation of the head produce anatomical changes that seem to make cannulation of the jugular difficult.