Anal endosonography and its role in assessing the incontinent patient.

Anal endosonography is now recognized as an important investigation in the assessment of faecal incontinence. The endosonographer needs to be aware that the anatomy of the anal sphincter is complex and therefore there can be pitfalls in the interpretation of images. The findings have clinical implications on subsequent management and can contribute to prognosticating outcome. However, anal endosonography has a complementary role and other investigations, such as anal manometry, should be performed before intervention.