The article shows the wide possibilities of computed tomography (CT) diagnosis of the topography of muscles forming the external sphincter of the anus (ESA) in patients with developmental anorectal anomalies and in trauma and rupture of the perineum. It is shown that in anorectal anomalies with fistulas opening into the urinary system the puborectal muscular sling is "drawn up" ventrally in relation to the external sphincter elements lying closer to the surface. Analysis of the results of CT examination of the pelvic floor in 16 children with anorectal anomalies showed that the degree of development of the sphincter muscles does not always correspond to the level of atresia. For instance, the mass of the ESA muscles is manifested more in some forms of cloacal atresia than in "tubular" stenoses of the rectum (anorectal stenosis--Curravino-triad component) (G. Curravino, 1981). CT examination of children with this complex of caudal anomalies allowed the authors to reveal a fourth constant component: dysplasia of the pelvic floor and a specific developmental anomaly of the anal sphincter. CT is the method of choice in the examination of children with this pathological condition because it makes it possible to recognise the presence of presacral masses. The use of CT in traumas and ruptures of the perineum allows the depth and extension of ruptures of the ESA muscles to be authentically determined.