title: Vertebral level of Tuffier's line measured by ultrasonography in parturients in the lateral decubitus position.
abstract: BACKGROUND
  It is known that Tuffier's line intersects the spine at the L4 spinous process or at the L4-L5 intervertebral space. Full term parturient women undergo various physical changes. Therefore, determining the vertebral level with Tuffier's line based on palpation inevitably is not very accurate. The aim of this study was to use ultrasound to verify the difference between vertebral levels for the palpated Tuffier's line in parturient and non-parturient women in the lateral decubitus position.
  
  
  METHODS
  We consecutively enrolled 40 parturient women at 37-41 weeks of gestation and 40 non-parturient women scheduled for regional anesthesia. In the left lateral position, the location of the vertebra was identified using ultrasonography. We marked every intervertebral space from L5 to L2 vertebra, divided each spinous process into two equal parts, and numbered the spaces sequentially from 1 to 9. We drew a Tuffier's line by palpating, recorded the vertebral level that this line intersected.
  
  
  RESULTS
  The mean value of an arbitrary number of vertebral level of Tuffier's line was 6.4 ± 0.9 in the non-pregnant group and this represents L4-lower vertebral level. In the pregnant group, the mean value was 3.0 ± 1.0 which represents L3-lower vertebral level. There was a significant difference between the two groups (P < 0.05).
  
  
  CONCLUSIONS
  We compared using an available ultrasound technique the vertebral levels intersected by the palpated Tuffier's line between parturient and non-parturient women and found that the vertebral levels were more cephalad in the parturient women compared to the non-parturient women.
authors.affiliation: Department of Anesthesiology and Pain Medicine, Ewha Womans University School of Medicine, Seoul, Korea.
authors.forename: Se Hee
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Department of Anesthesiology and Pain Medicine, Ewha Womans University School of Medicine, Seoul, Korea.
authors.forename: Dong Yeon
authors.initials: DY
authors.lastname: Kim
authors.affiliation: Department of Anesthesiology and Pain Medicine, Ewha Womans University School of Medicine, Seoul, Korea.
authors.forename: Jong In
authors.initials: JI
authors.lastname: Han
authors.affiliation: Department of Anesthesiology and Pain Medicine, Ewha Womans University School of Medicine, Seoul, Korea.
authors.forename: Hee Jung
authors.initials: HJ
authors.lastname: Baik
authors.affiliation: Department of Anesthesiology and Pain Medicine, Ewha Womans University School of Medicine, Seoul, Korea.
authors.forename: Hahck Soo
authors.initials: HS
authors.lastname: Park
authors.affiliation: Department of Anesthesiology and Pain Medicine, Ewha Womans University School of Medicine, Seoul, Korea.
authors.forename: Guie Yong
authors.initials: GY
authors.lastname: Lee
authors.affiliation: Department of Anesthesiology and Pain Medicine, Ewha Womans University School of Medicine, Seoul, Korea.
authors.forename: Jong Hak
authors.initials: JH
authors.lastname: Kim
keywords: Parturient; Spinal anesthesia; Ultrasonography; Vertebra