Anorectal morphology and function: analysis of the Shafik legacy.

Following the untimely death of Professor Ahmed Shafik, the authors decided to analyse his published work on the anatomy and physiology of the anorectal area, reconciling this body of data with current imaging and physiological techniques. All available papers as indexed by PubMed pertaining to the anorectal area were obtained and reviewed. The anatomical data was compared with historical representations and current new imaging modalities. The original 'triple-loop' theory of the anatomical disposition of the external anal sphincter has been confirmed by coronal and coronally reconstructed imaging modalities. There is variance between the Shafik and other descriptions of the anatomy of the longitudinal muscle and its importance in the definition of perianal spaces which are important in the spread of perirectal sepsis and in intersphincteric rectal dissection. Current dynamic defaecography would suggest a more complex levator plate function in squeeze and straining than that originally suggested by Shafik as a primary defaecatory role for the levator muscle. The body of work by Professor Shafik has reorganized our understanding of the external anal sphincter and the function of the levator during defaecation. Future studies should assess anatomical and physiological variances using new technology in health and in specific disease states.