[Anal fissure].

The etiology of anal fissure remains controversial and the multiplicity of theories suggests a number of different causes. Histologic and manometric studies have shown abnormalities of the internal anal sphincter in this condition. The clinical features are described briefly. Generally accepted principles of medical management have been arrived at by common sense rather than through well-controlled studies. Surgical treatment in its various forms consists in producing a laceration of the internal sphincter. Lateral sphincterotomy gives the best results from the point of view of recurrence or incontinence; posterior sphincterotomy, which leads to a key-hole deformity, appears to produce the highest incidence of incontinence. It is not possible to determine from published reports the respective advantages of complete versus partial posterior sphincterotomy.