Observations on the human cardia at operation.

The pressure required to overcome resistance at the oesophagogastric junction was measured at operaaon in fifteen subjects and found to be 20 cm H,O from both oesophageal and gastric aspects. Altering the angle of entry of the oesophagus to the stomach by fundal depression or occlusion did not affect these pressures, in contradistinction to the results in the cadaver (Marchand, 1955). Dividing the vagus nerves increased the resistance to intragastric pressure to 55 cm H,O without altering the resistance to intraoesophageal pressure change. A similar effect was seen with atropine given intravenously. The results support the view of a true sphincter at the cardia with a mechanism for augmenting the resistance to gastric regurgitation.