title: Determining the level of the dural sac tip: magnetic resonance imaging in an adult population.
abstract: OBJECTIVE
  To determine the variation in the location of the dural sac (DS) in a living adult population and to correlate this position with age and sex.
  
  
  METHODS
  T2-weighted, midline, sagittal, spin-echo magnetic resonance imaging (MRI) studies of 743 patients were assessed to identify the tip of the DS. This location was recorded in relation to the upper, middle, or lower third of the adjacent vertebral body or the adjacent intervertebral disk.
  
  
  RESULTS
  Frequency distribution for levels of termination of the DS on MRI demonstrated that the end of the DS was usually located at the upper one-third of S2 (25.2%). The mean level in females was also the upper one-third of S2 (26.5%) and in males the lower one-third of S2 (24.1%). The overall mean DS position was mostly at the upper one-third of S2. No significant differences in DS position were seen between male and female patients or with increasing age.
  
  
  CONCLUSIONS
  It is important to know the possible range for the termination level of the DS when performing caudal anesthesia and craniospinal irradiation in some clinical situations. The distribution of DS location in a large adult population was shown to range from the L5-S1 intervertebral disk to the upper third of S3 vertebrae.
authors.affiliation: Department of Radiology, Faculty of Medicine, Cukurova University, Balcali Hospital, Adana, Turkey. fbinokay@cu.edu.tr
authors.forename: F
authors.initials: F
authors.lastname: Binokay
authors.forename: E
authors.initials: E
authors.lastname: Akgul
authors.forename: K
authors.initials: K
authors.lastname: Bicakci
authors.forename: S
authors.initials: S
authors.lastname: Soyupak
authors.forename: E
authors.initials: E
authors.lastname: Aksungur
authors.forename: Y
authors.initials: Y
authors.lastname: Sertdemir
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D004388:Dura Mater / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D008161:Lumbosacral Region; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012189:Retrospective Studies; D012737:Sex Factors