Nat. Rev. Gastroenterol. Hepatol. doi:10.1038/nrgastro.2016.53 Figure 1 Four main subtypes of dyssynergic defecation can be observed by anorectal manometry Figure 1 | Four main subtypes of dyssynergic defecation can be observed by anorectal manometry. Type I: adequate rectal push effort with paradoxical anal sphincter contraction. Type II: inadequate rectal push effort with paradoxical anal sphincter contraction. Type III: adequate rectal push effort but inadequate relaxation (<20%) of anal sphincter pressure. Type IV: inadequate rectal push effort and also inadequate relaxation (<20%) of anal sphincter pressure. Rao, S. S. C. et al. (2016) Diagnosis and management of chronic constipation in adults Nat. Rev. Gastroenterol. Hepatol. doi:10.1038/nrgastro.2016.53