The　pathophysiology　and　pathoanatomy　of　DPS　were　analyzed　by　mechanicsFrom　the　films　of　defecography,four　kinds　of　coordinate　curves　of　the　upper　part　of　anal　canal　were　found　in　the　sagittal　plane　in　26　casesAccording　to　the　fundamentals　of　mechanics,the　injure　and　hypointense　of　the　connective　tissue　of　the　pelvic　floor,especially　the　anococcygeal　ligament,are　the　cause　of　Perineum　Descending.

Objective:To evaluate a new operation produre for the treatment of circular mixed hemorrhoids;not only obliterating symptom disposably,but also protecting the integrality and furthest of anal canal epithelium and padding, Treitz s Muscle,and retaining nomal functions of anus.

Objective To explore the nursing approach of photodynamic therapy(PDT) of perianal/anal canal condyloma acuminatum with topical adminstration of 5-aminolevulinic acid(ALA).

Magnetic resonance imaging of the normal anatomy of anal canal;

The demonstration of the normal anal canal and perianal structures by high-resolution magnetic resonance imaging with a phased-array coil;

Topographic distribution of the intramural microvessels of the anal canal in fetus and its clinical significance;