title: Is the human round window really round? An anatomic study with surgical implications.
abstract: OBJECTIVE
  Human round window (RW) presents anatomic variations that may influence surgical approach.
  
  
  BACKGROUND
  The true shape of the human RW has been divisive since its first description in 1772 by Antonio Scarpa. Introduction of novel surgical strategies in recent years have raised its significance. Here, the human RW size and shape variations were documented in microdissected human temporal bones.
  
  
  METHODS
  An archival collection of human microdissected temporal bones was analyzed. RW rim could be delineated and photographed from the labyrinthine aspect and its topography assessed.
  
  
  RESULTS
  Human RW is seldom round but ovoid or orthogonal, skewed, and nonplanar (saddlelike). Membrane is fan shaped or conical with an anteroinferior and a posterosuperior part. The mean longest diameter was 1.90 mm, and the smallest one is 1.54 mm. The mean diameter from the crista fenestra was 1.31 mm. The mean area of the RW was 2.08 mm, which varied between 0.99 and 3.20 mm. The crista fenestrae of the anterior component form a "doorstep" that may limit the entry to the scala tympani from the RW niche.
  
  
  CONCLUSIONS
  The alternate anatomic features of the human RW may influence its surgical access and designs of implants aimed at targeting this region.
authors.affiliation: *Department of Neurology, Mental Health and Sensory Organs, Otorhinolaryngologic Unit, Medicine and Psychology, Sapienza, Rome, Italy; and †Department of Surgical Sciences, Head and Neck Surgery, Section of Otolaryngology, Uppsala University Hospital, Uppsala, Sweden.
authors.forename: Francesca
authors.initials: F
authors.lastname: Atturo
authors.forename: Maurizio
authors.initials: M
authors.lastname: Barbara
authors.forename: Helge
authors.initials: H
authors.lastname: Rask-Andersen
mesh_terms: D002102:Cadaver; D006801:Humans; D042282:Microdissection; D012405:Round Window, Ear / Q000033:anatomy & histology*