Figure 2 - Relationship of upper esophageal high-pressure zone (UEHPZ) to the pharyngoesophageal muscles.

Data compiled from three different studies of the position of the UEHPZ with respect to individual pharyngeal muscles based on combined manometric and videofluoroscopic studies. Note that the peak pressures of the UEHPZ in humans at rest with the head fixed in all three studies coincides with the lower border of the IPC. A, arytenoid; AEF, aryepiglottic fold; CC, cricoid cartilage; ESO, esophagus; IPC, inferior pharyngeal constrictor; PE, pharyngoesophageal; TR, tracheal ring; VC, vocal cord. (Source: Adapted from Goyal et al.,¹² with permission of Springer Science and Business Media.)