Anorectal manometry is a way of investigation for anti-rectal sphincters. In this paper we evaluated the usefulness of anorectal manometry in constipation patients and compared the anal spnincter function in control, constipation and encopresis patients.

We analysed the data of anorectal function studies in normal children (control, n=11), children with constipation (constipation group, n=20) and children with encopresis (encopresis group, n=16).

The specific manometric parameters in normal children were like as follows; external anal sphinter pressure 21.0±8.00 mmHg, internal anal sphicter pressure 30.0± 14.57 mmHg, conscious rectal sensitivity threshold 11.4±4.52 mmHg. The above results were not different from that of previous studies except conscious rectal sensitivity threshold, which was slightly lower than that of others. Internal and external anal sphincter pressure were elevated significantly in constipation and encopresis groups than in control, which results was the same in conscious rectal sensitivity threshold. But the values of rectoanal inhibitory threshold and percent relaxation of rectoanal inhibitory reflex were not different among control group, constipation group and encopresis group. External sphincter activity was increased during the act of bearing down for defecation in none of the child in control group, in 6 of 17 children in constipation group and 5 of 12 children in encopresis group.

With the results of above we could say that complete history taking and physical examination are important in diagnosis of constipation, and we could say also that the anorectal manometry was a valuable tool to understand the physiology of normal defecation and the pathophysiology of constipation and encopresis.