The Pyloric Sphincteric Cylinder in Health and Disease

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Chapter 13 (page 56)

Contraction Patterns of Distal 3-4 cm of Stomach

Details of the contractions of the distal 3.0 to 4.0 cm of the stomach, as seen radiologically, have been documented (Keet l957, l962). While the descriptions remain valid, room exists for minor modifications and further clarification. Moreover, in the previous descriptions only maximal (or complete) contractions, i.e. those bisecting the lumen, were considered; in the present investigation the more shallow (or incomplete) contractions will also be dealt with. Consequently the following additional studies have been done.

Radiological Studies

Patients and Methods

The contractions were studied in (1) the group of 100 adult, ambulatory outpatients mentioned in Chap. 12; (2) a group of 20 patients in whom previous endoscopic examinations had proved the oesophagus, stomach and duodenum to be normal. (These patients had been referred for radiographic studies to confirm the absence of hiatus hernia).

Each patient had a conventional upper gastrointestinal barium study, the contractions being observed in both the erect and supine positions. As people generally have meals in a sitting position, studies were also performed with the subject sitting in 5 of the 20 endoscopically normal cases. Localized "spot" exposures were done occasionally for record purposes.

Ethical Considerations. As the contractions were studied during the ordinary course of events, the examinations were not prolonged to any appreciable extent, which means that any possible extra radiation to the patient was negligible.


Irrespective of the position of the patient, definite "patterns" of contraction occurred.

In all 120 cases a stage was awaited in which the duodenal cap was filled, in which the normal division between the stomach and duodenum (the pyloric ring) was clearly visible, and in which the pyloric region as well as the duodenal bulb were free of contractions, i.e. a motor quiescent phase (Fig. 11.1, 11.2). Measurements at this stage showed that the width of the normal indentation between the stomach and duodenum (the pyloric ring) on the lesser curvature, was more or less equal to the width on the greater curvature (Fig. 13.5) (see also Fig. 11.1 and 11.2). At this stage it is also seen that the pyloric aperture is patent, that it contains barium and that its diameter can be measured.

Fig. 13.5. Normal pyloric ring (arrow) in motor quiescent phase. Width of ring on lesser curvature more or less equal to that on greater curvature. Note patent pyloric aperture with diameter of 9 mm, containing barium

After a variable interval peristaltic contractions commenced in the gastric corpus in all cases. These narrow, annular waves were seen to proceed along the body of the stomach in a caudal direction as far as a point 3.0 to 4.0 cm proximal to the pyloric aperture. At this point each caudally travelling peristaltic wave came to a halt, i.e. it failed to advance any further, and ended in a concentric or cylindrical contraction of the entire distal 3.0 to 4.0 cm of the stomach (Fig. 13.6).

Fig. 13.6. Point at which peristaltic wave stops (curved arrows). Pyloric aperture (straight arrow). The region between the curved and straight arrows is distal 3-4 cm of stomach.

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