Torsion of the abomasum in ruminants: diagrammatic representation of rotary movements based on post-mortem findings.

A theoretical analysis of the types of displacement of the abomasum in the abdomen is presented based on a study of forty-seven post-mortem examinations of calves, cows, lambs and sheep showing right-sided abomasal displacement and production of knots. These displacements are quantified following the introduction of a dual-axial system. One system (XYZ) related to displacements of the abomasum on a pendulum model, the point of suspension being situated on the visceral surface of the liver and the arms consisting of parts of the digestive tract adjacent to the abomasum. The other system (x1y1z1) comprises axes centered on the abomasum, about which this organ was able to rotate without changing its position in the abdomen. In order to make quantification of the displacements and deformations possible, the term twine is introduced. Twining results from interlacing of sections of the digestive tract, which are not normally adjacent. This limits the concept of torsion to helices appearing in the pyloro-duodenal region and the omaso-abomasal junction. To identify the various forms of abomasal displacement, a new terminology is introduced and basic elements suggested to make quantifications possible.