[Simultaneous electromyographic and manometric study of the function of the anorectum (author's transl)].

The contractile and myoelectrical activity of the internal anal sphincter (IAS) and the rectum 2 and 4 cm orad of the IAS were measured in 20 healthy volunteers. Perfused manometry catheters and bipolar wire electrodes penetrating the musculature were used. We evaluated anorectal activity under basal conditions and after provocation of the defecation reflex by inflation (20 to 150 ccm) of a balloon in the rectum. Basal pressure in the IAS was 54.9 +/- 5.2 (SEM) mm Hg. If fluctuated spontaneously. The IAS generated sinusoidal slow potentials (LP) continuously, mean frequency was 21.14 +/- 0.43 cycles/min (cpm). LIP in the rectum 2 and 4 cm orad of the IAS occurred intermittently, their frequency was 9.72 +/- 0.45 and 8.95 +/- 0.30 cpm, respectively. In addition, the rectum generated LP of 3.10 +/- 0.94 cpm temporarily. Provocation of the defecation reflex caused the IAS to relax partially at distending volumes of 20 ccm and completely at volumes of 50 to 100 ccm. At the same time, the myoelectrical activity of the IAS became irregular. An initial interruption of the LP of 4 to 12 second duration occurred in most experiments. The defecation reflex was accompanied by a brief contraction and an increase in spike activity in the rectum. Thus, the simultaneous electromyographic and manometric examination of the anorectum yields quantitative data on the function of this area. The diagnostic values of the procedure has to be tested in comparative studies of patients without and with functional disorders of the colon and anorectum.