Fig. 2

a Median sagittal plane in a male cadaveric left hemipelvis. S, superior; A, anterior; P, posterior; I, inferior; R, rectum; RSL, rectosacral ligament; LAM, levator ani muscle; DEAS, deep part of the external anal sphincter; SEAS, superficial part of the external anal sphincter; ScEAS, subcutaneous part of the external anal sphincter; IAS, internal anal sphincter; Mc, the rectal mucosa; Sm, rectal submucosa. The white asterisk represents the intersphincteric space. The dashed red line represents the surgical plane. The red shade represents the excised specimen. b Median sagittal plane in a male cadaveric right hemipelvis. S, superior; A, anterior; P, posterior; I, inferior; R, rectum; RSL, rectosacral ligament; LAM, levator ani muscle; DEAS, deep part of the external anal sphincter; SEAS, superficial part of the external anal sphincter; ScEAS, subcutaneous part of the external anal sphincter; IAS, the internal anal sphincter. The white asterisk represents the intersphincteric space. The dashed red line represents the surgical plane. The red shade represent the excised specimen. c Median sagittal plane in a male cadaveric right hemipelvis. S, superior; A, anterior; P, posterior; I, inferior; R, rectum; RSL, rectosacral ligament; LAM, levator ani muscle; DEAS, deep part of the external anal sphincter; SEAS, superficial part of the external anal sphincter; ScEAS, subcutaneous part of the external anal sphincter; IAS, internal anal sphincter. The white asterisk represents the intersphincteric space. The dashed white line represents external anal sphincter complex. The red shade indicates the excised part of the external anal sphincter and levator ani muscle and the blue shade indicates the part of the external anal sphincter that was left intact. Courtesy of Sigmar Stelzner and Thilo Wedel, Institute of Anatomy, University of Kiel. With permission of Institute of Anatomy, University of Kiel, Germany