title: The pars intermedia: an anatomic basis for a coordinated vascular response to female genital arousal.
abstract: BACKGROUND
  The pars intermedia is an area of the vulva that has been inconsistently described in the literature.
  
  
  OBJECTIVE
  We conducted anatomic studies to better describe the tissues and vascular structures of the pars intermedia and proposed a functional rationale of the pars intermedia in the female sexual response.
  
  
  METHODS
  Nine cadaveric vulvectomy specimens were used. Each was serially sectioned and stained with hematoxylin and eosin and Masson's trichrome.
  
  
  METHODS
  Histologic ultrastructural description of the pars intermedia.
  
  
  RESULTS
  The pars intermedia contains veins traveling longitudinally in the angle of the clitoris, supported by collagen-rich stromal tissues. These veins drain the different vascular compartments of the vulva, including the clitoris, the bulbs, and labia minora; also, the interconnecting veins link the different vascular compartments. The pars intermedia is not composed of erectile tissue, distinguishing it from the erectile tissues of the corpora cavernosa of the clitoris as well as the corpus spongiosum of the clitoral (vestibular) bulbs.
  
  
  CONCLUSIONS
  The venous communications of the pars intermedia, linking the erectile tissues with the other vascular compartments of the vulva, appear to provide the anatomic basis for a coordinated vascular response during female sexual arousal.
authors.affiliation: Department of Urology, University of Washington School of Medicine, Seattle, WA 98195, USA. csshih@uw.edu
authors.forename: Cheryl
authors.initials: C
authors.lastname: Shih
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Cold
authors.forename: Claire C
authors.initials: CC
authors.lastname: Yang
mesh_terms: D001143:Arousal; D002102:Cadaver; D002987:Clitoris / Q000098:blood supply; D005260:Female; D006801:Humans; D012725:Sexual Behavior; D014680:Veins / Q000648:ultrastructure; D014844:Vulva / Q000098:blood supply*