title: Perianal anatomy in non-abused preschool children.
abstract: The purpose of this study was to describe the normal variation in perianal anatomy in preschool children, selected for non-abuse, and to compare the findings in two examination positions. A letter of invitation was sent to 3773 children, after which 305 children (103 boys and 202 girls) were recruited. Inclusion in the study was based on self-selection, whereby parents who did not suspect any occurrence of sexual abuse of their child gave informed consent to participate. The mean age of the children was 5.63 y (range: 5.13-6.75). An anal examination was performed in the left lateral position (LLP) and the prone knee-chest position (KCP), for approximately 30 s each. A colposcope and a camera were used. All data were systematically analysed for gender differences, and a paired sample test was used to compare findings in LLP and KCP. Venous congestion in LLP and external anal dilatation in both positions were significantly more common in girls, while midline depressions and smooth areas (both positions) were significantly more common in boys. External and total anal dilatation, midline smooth areas and depressions and the occurrence of a prominent anal verge were significantly more common in the KCP. The finding of total anal dilatation was rare.
  
  
  CONCLUSIONS
  We observed several gender and position differences in perianal anatomy, and most of these findings seem to be related to structure and tone in the anal muscles.
authors.affiliation: Department of Women's and Children's Health, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim. arne.k.myhre@medisin.ntnu.no
authors.forename: A K
authors.initials: AK
authors.lastname: Myhre
authors.forename: K
authors.initials: K
authors.lastname: Bemtzen
authors.forename: D
authors.initials: D
authors.lastname: Bratlid
mesh_terms: D001003:Anal Canal / Q000033:anatomy & histology* / Q000473:pathology; D002648:Child; D002650:Child Abuse, Sexual / Q000175:diagnosis*; D002675:Child, Preschool; D004108:Dilatation, Pathologic; D005260:Female; D006801:Humans; D008297:Male; D011187:Posture; D012016:Reference Values; D012737:Sex Factors; D018709:Statistics, Nonparametric