Figure 2 - Demonstration of "physiologic herniation" during swallow using endoscopically placed mucosal clips.

a: Before swallow. Clip B marks the position of the squamocolumnar junction 0.4 cm distal to the hiatus and 3.5 cm distal to the anchor point on the vertebral body (V). Clip A is affixed to the esophageal mucosa 3.1 cm proximally. Clip movements are referenced to point V on the vertebral column. b: At the time of maximal esophageal shortening, clip B is 1.8 cm proximal to the hiatus and 2.0 cm distal to point V. The distance between clips A and B is reduced to 2.2 cm, indicative of 29% shortening. c: As elongation proceeds, first both clips descend, after which clip B descends, stretching the A-B segment back to its initial length. d: After swallow, clip B is again at the level of the hiatus. (Source: Kahrilas et al.,⁹ with permission from American Gastroenterological Association.)