What Is the Pyloric Sphincteric Cylinder Concept in *The Pyloric Sphincteric Cylinder in Health and Disease*?

The pyloric sphincteric cylinder is the central anatomical concept of A. D. Keet's book The Pyloric Sphincteric Cylinder in Health and Disease: instead of picturing the pylorus as a narrow ring of muscle that simply opens and closes, Keet treats it as a muscular cylinder — a segment with length as well as circumference — whose behaviour helps explain gastric motility, trituration, emptying of liquids and solids, and duodeno-gastric reflux. The book was first published by Springer-Verlag in 1993 (ISBN 3-540-55814-4 and 3-387-55814-4) and was later placed in full on the Internet with copyright returned to the author, so the whole treatise can be read online for research purposes.

Cylinder versus ring: what actually changes

A sphincteric ring model implies a thin muscular band that constricts at a single plane. A sphincteric cylinder model implies a longer tubular segment of pyloric musculature that can contract, relax, shorten, or lengthen as a unit. That difference matters because many observations at the gastroduodenal junction — how contents are held back, ground, and released — are awkward to explain with a simple ring, but become more coherent when the pylorus is treated as a cylinder.

Keet builds this concept on earlier anatomical descriptions, specifically those of Cunningham (1906), Forssell (1913) and Torgersen (1942). The argument is that if the stomach's anatomy is read in that tradition, a range of physiological events in which the pylorus is implicated can be clarified.

What the concept is used to explain

According to the book's own summary, the cylinder concept is applied to:

• Gastric motility — how the pyloric region participates in the motor activity of the stomach rather than acting as a passive gate.
• Trituration — the grinding of solid food, which depends on the pylorus retaining particles while the antrum works on them.
• Emptying of liquids and solids — the two are handled differently, and a cylinder that can change shape and length offers a mechanism for that difference.
• Duodeno-gastric reflux — backward flow from duodenum to stomach, which depends on how the junction is configured at a given moment.

The same reasoning is extended to pathological conditions, including gastric and duodenal ulceration, some types of gastritis, diabetes mellitus, and pyloric carcinoma.

How the concept was investigated

The work originated in, and was managed from, the Department of Roentgenology at Tygerberg Hospital, the academic hospital of the Faculty of Medicine, University of Stellenbosch, South Africa. Roentgenology — a barium meal or upper gastrointestinal series — was used there as an investigative rather than a purely diagnostic tool. Keet notes that in this particular context roentgenology has certain advantages over endoscopy, while explicitly acknowledging that endoscopy is at present the investigation of choice in upper gastrointestinal pathology.

The findings from several modalities are discussed and compared in the book:

How the book is organised

The online edition lists 39 chapters, moving from anatomy and basic science to clinical conditions. A rough map:

• Foundations (Ch. 1–9): introduction, uncertain concepts, stomach and duodenal walls, submucous coat, mucosa, electrical potential difference at the gastroduodenal mucosal junction, vessels and lymphatics, nerves, regulatory peptides.
• Normal anatomy and imaging (Ch. 10–19): ultrasonography of normal anatomy, anatomy of the pyloric ring, the pylorus at rest (open or closed?), radiographic examination of normal motility, the pylorus at gastroscopy, manometry, myoelectric activity, ultrasonography of motility and emptying, radionuclides in gastric emptying, gastric tone and the cylinder.
• Disorders (Ch. 20–39): pylorospasm, congenital anomalies, partial or intramural gastric diverticulum, infantile and adult hypertrophic pyloric stenosis, focal hypertrophy and focal spasm, nausea/retching/vomiting, duodenogastric reflux, gastritis and erosions, gastric and duodenal ulceration, pyloroduodenal fistula, GERD, pyloric carcinoma, malignant lymphoma, malignancy at the gastro-oesophageal junction, sessile polyps, diabetes mellitus, mucosal prolapse, and acid corrosive injuries.

Who this resource is for

This is a specialist monograph, not an introductory text. It suits readers who already have some grounding in gastrointestinal anatomy or clinical practice and want a sustained argument about pyloric structure and function, together with a review of how different investigative methods compare. If you need a quick definition of the pylorus, a general anatomy reference will serve you better; if you want the cylinder-versus-ring reasoning and its clinical implications worked through in detail, this is the source.

The Internet edition was edited and published in 1998 by PLiG, and the publisher can be contacted at [email protected]. The work remains under copyright: all rights are reserved, and duplication or storage in a retrieval system requires prior permission from the current publishers.