Figure 1

Extrinsic and intrinsic components for the GEJHPZ in 15 normal control subjects. Panel A represents the pressure components during full inspiration. Panel B represents the pressure components during full expiration. The x axis represents the relative distance from the start of right crural diaphragm, and the y axis represents the pressures relative to the gastric pressures. The red curves are preatropine pressures, reflecting the combined external and internal sphincter pressures. The green curves are the postatropine pressures (extrinsic crural sphincter pressures). The blue curves are the subtracted (preatropine minus postatropine) pressures, reflecting the muscarinic intrinsic sphincter components. The intrinsic sphincter pressure curves display two peaks in both full inspiration and full expiration. The distal peak reflects the gastric sling fiber/clasp fiber complex, whereas the proximal peak reflects a physiologic LEC within the abdominal esophagus that overlaps the crural sphincter.