Choose the distance in centimeters from the upper incisor teeth at which the following radiographically identified esophageal lesions would be encountered endoscopically:

1. B. 15 cm.

2. C. 25 cm.

3. D. 30 cm.

DISCUSSION: A barium esophagogram should be obtained routinely before performing elective esophagoscopy. The location of an esophageal lesion seen on the barium swallow study can be related to adjacent anatomic landmarks. This allows the endoscopist to anticipate the level (as measured from the upper incisor teeth) where he should expect to see the abnormality at esophagoscopy. For example, the upper esophageal (cricopharyngeal) sphincter is generally seen at the level of the C7–T1 vertebrae radiographically and at 15 cm. endoscopically. This is the level at which the mouth of a Zenker's diverticulum is seen. The tracheal bifurcation occurs at the level of the T4 or 25 cm. from the upper incisors endoscopically; a traction (parabronchial) diverticulum at the level of the carina on a barium esophagogram will be seen at approximately 25 cm. The esophagogastric junction occurs at approximately the level of T11, 40 cm. from the upper incisors; a tumor 10 cm. proximal to the esophagogastric junction stricture is seen endoscopically at 30 cm.