[Pathologic and functional anatomy basis of intersphincteric resection]

The anorectum is a complex region, whose anatomic structure is the basis and premise of intersphincteric resection (ISR) for low rectal cancer. With the development of pelvic surgery and minimally invasive surgery, the anatomic approaches, surgical planes, extent of excision and reconstruction strategies of ISR have been better understood. Surgeons can furthest preserve anal function as well as adhere to the principles of radical resection. However, the anatomy of the anorectum has not been fully understood. We hope further exploration of the anal canal anatomy, including the perirectal fascia, rectourethral muscle, anococcygeal ligament, hiatal ligament, levator ani muscle, internal and externals phincter, intersphincteric nerves, conjointed longitudinal muscle, intersphincteric spaces and the surgical approaches, by reviewing relevant literatures combined with the experiences of our clinical practice and applied anatomy, will help to improve the accuracy of the surgeries and increase the oncologic and functional outcomes of ISR.