Role of magnetic resonance defecography in the assessment of obstructed defecation syndrome

Figure 3 Sagittal T2-weighted image illustrating the placement of various reference lines. The pubococcygeal line (PCL), denoted by the red line, spans from the inferior aspect of the pubis anteriorly to the last coccygeal articulation posteriorly. The H-line, represented by the green line, extends from the inferior aspect of the pubis anteriorly to the posterior wall of the anorectal junction. The M-line, depicted by the yellow line, is drawn perpendicularly to the PCL, originating from the posterior point of the H-line.