Chapter 13 (page 63)

The Pyloric Sphincteric Cylinder in Health and Disease

Go to chapter: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39
Chapter 13 (page 63)

During contraction of the sphincteric cylinder the folds changed in direction, becoming progressively more longitudinal, and with maximum contraction only longitudinal folds were present in the fully contracted pyloric canal (Fig. 13.17). This was a regular occurrence in all our normal cases, including those described here, and appears to be one of the best examples of co-ordinated movements between the muscularis externa and mucosa (muscularis mucosae) occurring in the gastro-intestinal tract.

Fig. 13.17. Sphincteric cylinder contracted (arrows). The folds have changed in direction to become longitudinal. RPL, right pyloric loop; LPL, left pyloric loop. Note pseudodiverticulum between loops

In some of our normal cases not only a change in direction, but also a cephalad movement of the folds occurred during contraction of the sphincteric cylinder. The following is an example:

Case Report

Case G.O., 35 year old male. During the radiological examination a stage was awaited in which the pyloric shincteric cylinder was relaxed and distended with barium, while the part of the stomach on its oral side (Forssell's sinus) was also relaxed but filled with air. At this stage the mucosal folds in the cylinder were circular. During contraction of the cylinder the folds changed to longitudinal, at the same time moving in an orad direction and jutting into the sinus, forming a lobulated, intraluminal defect which had not been present previously (Fig. 13.18). Not only the folds were forced in an orad direction, but some of the barium in the cylinder was squirted orally to enter the sinus. The process may also be described as follows: During contraction of the pyloric sphincteric cylinder retropulsion of its mucosal folds, as well as some of its barium contents, occurred through the partially contracted left pyloric loop. During this contraction no barium was seen to enter the duodenum, indicating closure of the pyloric aperture, due to contraction of the right pyloric loop.

Fig. 13.18. Case G.O. Contraction of sphincteric cylinder and its right loop, closing the pyloric aperture (straight arrow). Retropulsion of mucosal folds (curved arrows) and barium (open arrow)

Further evidence that the mucosa of the cylinder may move in an orad direction during its contraction is seen in Chap. 36, cases 36.1 and 36.2. In these cases broad-based, sessile mucosal polyps in the inactive, relaxed cylinder, moved orally during contraction of the cylinder. The orad movement of the mucosa, while occurring normally, is not easily demonstrable during the conventional barium studies, but retropulsion of barium during contraction of the cylinder can often be shown; this should not be mistaken for duodenogastric reflux (Chap. 27).

Further evidence of co-ordinated movements between the muscularis externa and mucosa in the small bowel was presented by Sloan (l957). A correlation was found between the direction of the mucosal folds on the one hand, and the degree of distension or contraction of the walls on the other. During life longitudinal folds were seen to be associated with peristaltic activity. This feature could not be reproduced in anatomical specimens fixed in formalin.