Morphological properties and residual strain along the small intestine in rats

Figure 1 Definition of the zero-stress state. Traditionally, the zero-stress state is characterized by an opening angle defined as the angle subtended by two radii drawn from the mid-point of the inner wall to the inner tips of two ends of the sector in the zero-stress state. The opening angle is denoted by theta;. The labels m and s denote the mucosal and serosal surfaces and a is the line cutting. The angle between the tip tangents, which is described in the text, is denoted by Ψ. The angles between the tangents at the tip of the sector and the line joining the tips are designated as α and α', respectively. The mean value (α + α')/2 is referred to as the mean tangential angle.