Section: USMLE


6) In a normal individual, a tube with a transducer at its tip is swallowed and passed an unknown distance down the esophagus. Between swallows it records a pressure of 25 mm Hg. A small amount of water is swallowed. Within 2 seconds, the pressure falls to 5 mm Hg, where it remains until returning to its resting pressure 6 seconds later. In a patient with achalasia, the transducer is advanced to the same location. Between swallows, it records a pressure of 30 mm Hg. After swallowing, the pressure fails to decrease at all. In which of the following sites is the transducer most likely located?