Sz. Lin et al., THE PHRENIC AMPULLA - DISTAL ESOPHAGUS OR POTENTIAL HIATAL-HERNIA, American journal of physiology: Gastrointestinal and liver physiology, 31(2), 1995, pp. 320-327
The mechanics of phrenic ampullary emptying were analyzed to determine
whether this structure functions in a manner similar to the tubular e
sophagus or a hiatal hernia. Simultaneous videofluoroscopy and intralu
minal manometry of the gastroesophageal junction were done during bari
um swallows in 18 normal volunteers. Esophageal emptying was studied w
ithout any external influences, during abdominal compression with a cu
ff inflated to 100 mmHg, during a Muller maneuver, and after medicatio
n with atropine. The key finding of the study was that ampullary empty
ing was distinct from esophageal bolus transport in several ways: the
propagation velocity of the clearing wave was slower, the maximal cont
act pressures achieved after luminal closure were lower and unaffected
by atropine or outflow obstruction, and ampullary emptying was driven
by a hydrostatic pressure difference between the ampulla and stomach
rather than by a peristaltic contraction. Increased bolus volume sligh
tly enlarged the ampulla. Taken together, these findings suggest that
ampullary emptying occurs, in part, as a result of the restoration of
esophageal length (presumably by tension from the phrenoesophageal mem
brane) rather than as a result of an aborally propagated contraction.
As such, a normal phrenic ampulla is analogous to a small reducing hia
tal hernia. We speculate that overt hernia formation occurs as a resul
t of progressive degeneration of the phrenoesophageal membrane.