PURPOSE:This study was designed to determine the importance of innervation of striated anal sphincters, one of the most important structures in idiopathic fecal incontinence.METHODS:Forty‐three idiopathic, fecally incontinent patients (40 women and 3 men; mean age, 57.2±11 (range, 33‐77) years) underwent anorectal manometry and sphincteric electromyography. On the basis of electromyographic findings, patients were subdivided into three groups: Group A consisted of 21 patients with normal electromyography; Group B consisted of 14 patients with moderate denervation; Group C consisted of 8 patients with severe denervation. Manometric results from the patients were compared with those from 15 healthy subjects (8 women and 7 men; mean age, 35±12 (range, 15‐55) years).RESULTS:Incontinent patients had a shorter anal canal(P=0.005), and anal canal pressure was lower at rest(P<0.001), at contraction(P<0.001), and at coughing(P<0.001); rectal distention and rectal compliance were reduced (maximum tolerated volume,P<0.003; compliance at 200 ml,P=0.03; at 250,P<0.005; at 300 ml,P=0.03). No statistically significant differences were found between the manometric results of the three different groups of patients. A statistically significant linear correlation was reached by comparing the clinical severity of fecal incontinence with age(P=0.02) and some other manometric parameters: the pressure of the anal canal at rest(P<0.001) and at contraction(P<0.01); rectal compliance at 50 ml(P=0.03), 100 ml(P=0.004), and 150 ml(P=0.004).CONCLUSION:Clinical severity of fecal incontinence is correlated with some manometric parameters. Severity of denervation of the anal striated sphincters does not appear to influence severity of fecal incontinence.