title: The anatomy of the perineal body in relation to abdominoperineal excision for low rectal cancer.
abstract: OBJECTIVE
  Dissection of the perineal body (PB) during abdominoperineal excision (APE) for low rectal cancer is often difficult due to the lack of a natural plane of dissection. Understanding the PB and its relation to the anorectum is essential to permit safe dissection during the perineal phase of the operation and avoid damage to the anorectum and urogenital organs. This study describes the anatomy and histology of the PB relevant to APE.
  
  
  METHODS
  Six human adult cadaver pelvic exenteration specimens (three male, three female) from the Leeds GIFT Research Tissue Programme were studied. Paraffin-embedded mega-blocks were produced and serially sectioned at 50- and 250-μm intervals. Sections were stained by immunohistochemistry to show collagen, elastin and smooth muscle.
  
  
  RESULTS
  The PB was cylindrically shaped in the male specimens and wedge-shaped in the female ones. Although centrally located between the anal and urogenital triangles, it was nearly completely formed by muscle fibres derived from the rectal muscularis propria. Thick bundles of smooth muscle, mostly arising from the longitudinal muscle, inserted into the PB and levator ani muscle (LAM). The recto-urethralis muscle originated from the PB and separated the anterolateral PB from the urogenital organs.
  
  
  CONCLUSIONS
  Smooth muscle fibres derived from the rectal muscularis propria extend into the PB and LAM and appear to fix the anorectum. Dissection of the PB during APE is safe only when the smooth muscle fibres that extend into the PB are divided.
authors.affiliation: Department of Anatomy and Embryology, Leiden University Medical Center, Leiden, The Netherlands.|Pathology and Tumour Biology, Leeds Institute of Cancer and Pathology, University of Leeds, Leeds, UK.
authors.forename: A C
authors.initials: AC
authors.lastname: Kraima
authors.affiliation: Pathology and Tumour Biology, Leeds Institute of Cancer and Pathology, University of Leeds, Leeds, UK.
authors.forename: N P
authors.initials: NP
authors.lastname: West
authors.affiliation: Pathology and Tumour Biology, Leeds Institute of Cancer and Pathology, University of Leeds, Leeds, UK.
authors.forename: D
authors.initials: D
authors.lastname: Treanor
authors.affiliation: Pathology and Tumour Biology, Leeds Institute of Cancer and Pathology, University of Leeds, Leeds, UK.
authors.forename: D
authors.initials: D
authors.lastname: Magee
authors.affiliation: Pathology and Tumour Biology, Leeds Institute of Cancer and Pathology, University of Leeds, Leeds, UK.
authors.forename: N
authors.initials: N
authors.lastname: Roberts
authors.affiliation: Department of Surgery, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: C J H
authors.initials: CJ
authors.lastname: van de Velde
authors.affiliation: Department of Anatomy and Embryology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: M C
authors.initials: MC
authors.lastname: DeRuiter
authors.affiliation: Pathology and Tumour Biology, Leeds Institute of Cancer and Pathology, University of Leeds, Leeds, UK.
authors.forename: P
authors.initials: P
authors.lastname: Quirke
authors.affiliation: Department of Surgery, Catharina Hospital Eindhoven, Eindhoven, The Netherlands.
authors.forename: H J T
authors.initials: HJ
authors.lastname: Rutten
mesh_terms: D000005:Abdomen / Q000601:surgery*; D002102:Cadaver; D004210:Dissection / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D009130:Muscle, Smooth / Q000033:anatomy & histology; D010385:Pelvic Exenteration / Q000379:methods*; D010502:Perineum / Q000033:anatomy & histology* / Q000601:surgery*; D012004:Rectal Neoplasms / Q000473:pathology / Q000601:surgery*; D012007:Rectum / Q000033:anatomy & histology; D014521:Urethra / Q000033:anatomy & histology
keywords: Perineal body; abdominoperineal excision; longitudinal muscle; low rectal cancer; total mesorectal excision