title: Intrathecal movement and tension of the lumbosacral roots induced by straight-leg raising.
abstract: OBJECTIVE
  To obtain quantitative biomechanical data on the effects of different angles of straight-leg raising on intrathecal movements and tensions in the lumbosacral nerve roots in human cadavers.
  
  
  METHODS
  Eight embalmed human cadavers with no gross spinal pathology and no limitations in hip motion were used. We performed reverse straight-leg raising by hanging the left leg down from the table with the knee extended while measuring the movement and tension of nerve roots L2, L3, L4, L5, and S1 in 10-degree intervals for straight-leg raising from 0 to 70 degrees.
  
  
  RESULTS
  The mean intrathecal movements at 70 degrees were 0.55 mm, 0.54 mm, 0.96 mm, 1.54 mm, and 2.31 mm for roots L2, L3, L4, L5, and S1, respectively. The movements were statistically significant at >50 degrees for root L5 and at >40 degrees for root S1 (P < 0.05). The tension in the nerve roots with increasing angle of straight-leg raising increased from roots L2 to S1. The mean tensions at 70 degrees of straight-leg raising were 141.25 g, 168.75 g, 228.75 g, 280.00 g, and 493.75 g for roots L2, L3, L4, L5, and S1, respectively. The difference in tension was significant at >70 degrees for roots L2, L3, and L4 roots, at >40 degrees for root L5 root, and at >10 degrees for root S1 (P < 0.05).
  
  
  CONCLUSIONS
  The intrathecal movement and tension of the lumbosacral roots induced by straight-leg raising were <2.5 mm and <500 g, respectively. The movement and tension induced by straight-leg raising tended to be greater in more distal segmental roots.
authors.affiliation: Department of Rehabilitation Medicine, Pusan National University Hospital, Pusan National University College of Medicine, Pusan, Korea.
authors.forename: Hyun-Yoon
authors.initials: HY
authors.lastname: Ko
authors.forename: Byung Kyu
authors.initials: BK
authors.lastname: Park
authors.forename: Jae Heung
authors.initials: JH
authors.lastname: Park
authors.forename: Yong Bum
authors.initials: YB
authors.lastname: Shin
authors.forename: Hyun Joo
authors.initials: HJ
authors.lastname: Shon
authors.forename: Hyun Choong
authors.initials: HC
authors.lastname: Lee
mesh_terms: D001696:Biomechanical Phenomena; D002102:Cadaver; D005260:Female; D006801:Humans; D007866:Leg / Q000502:physiology*; D008160:Lumbosacral Plexus / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology*; D013126:Spinal Nerve Roots / Q000503:physiopathology*