Magnetic resonance defecography assessment of obstructed defecation syndrome in patients with chronic constipation in a tertiary care hospital

Table 1 Standard definitions used for interpretation of magnetic resonance defecography

Terminology	Definition
Pubococcygeal line	Line between the inferior margin of the symphysis pubis and the tip of the coccyx (Figure 1)
Anterior compartment	The posterior and most inferior part of the bladder base is the reference point
Middle compartment	The most anterior and inferior aspect of the cervix or posterosuperior vaginal apex in patients who have undergone hysterectomy is the reference point
Posterior compartment	The anterior aspect of the anorectal junction is the reference point
H-line	Distance between the inferior border of the pubic symphysis and the posterior wall of the rectum at the level of the anorectal junction. It indicates the width of the levator hiatus (Figure 1)
M-line	Vertical line drawn perpendicularly from the PCL to the posterior end of the H-line. It indicates the degree of decent of the levator hiatus or the degree of pelvic floor laxity (Figure 1)
Cystocele	Abnormal descent of urinary bladder at rest/straining using the PCL as the reference line (Figure 2)
Urethral hypermobility	Urethra rotation of > 30° from rest, from the vertical to horizontal axis
Prolapse (uterine/vaginal/cervical)	Abnormal descent of the anteroinferior aspect of the cervix/posterosuperior vaginal apex from the PCL (Figure 2)
Peritoneocele and enterocele	Inferior herniation of the peritoneal pouch along the anterior rectal wall with an increased distance between the vagina and rectum and wide rectovaginal fossa. Enterocele-abnormal descent of small bowel loops below the PCL (Figure 2)
ARA	Angle between the midline of the anal canal and a line tangent to the posterior rectal wall. At rest the normal angle measures approximately 70°-134° (Figure 3)
Rectocele	Abnormal bulge of the anterior rectal wall into the posterior vaginal wall (Figure 2)
Rectal intussusception	Infoldings of the full thickness of the rectal wall into the rectum (intrarectal/recto-rectal) or into the anal canal (intra- anal/anorectal) or beyond (extra-anal/rectal prolapse)
Pelvic floor descent	Excessive descent of the pelvic floor at rest or during defecation
Anismus	Lack of pelvic floor descent/prominent puborectalis impression/failure of opening of the ARA

ARA: Anorectal angle; PCL: Pubococcygeal line.