J Korean Neurosurg Soc.  2012 Jan;51(1):20-23. 10.3340/jkns.2012.51.1.20.

A Comparison Study on the Change in Lumbar Lordosis When Standing, Sitting on a Chair, and Sitting on the Floor in Normal Individuals

• Bae JS
• Jang JS
• Lee SH
• Kim JU

• KMID: 2190463
• DOI: http://doi.org/10.3340/jkns.2012.51.1.20

Abstract

OBJECTIVE
To compare radiographic analysis on the sagittal lumbar curve when standing, sitting on a chair, and sitting on the floor.
METHODS
Thirty asymptomatic volunteers without a history of spinal pathology were recruited. The study population comprised 11 women and 19 men with a mean age of 29.8 years. An independent observer assessed whole lumbar lordosis (WL) and segmental lordosis (SL) between L1 and S1 using the Cobb's angle on lateral radiographs of the lumbar spine obtained from normal individuals when standing, sitting on a chair, and sitting on the floor. WL and SL at each segment were compared for each position.
RESULTS
WL when sitting on the floor was reduced by 72.9% than the average of that in the standing position. Of the total decrease in WL, 78% occurred between L4 to S1. There were significant decreases in SL at all lumbar spinal levels, except L1-2, when sitting on the floor as compared to when standing and sitting on a chair. Changes in WL between the positions when sitting on a chair and when sitting on the floor were mostly contributed by the loss of SL at the L4-5 and L5-S1 levels.
CONCLUSION
When sitting on the floor, WL is relatively low; this is mostly because of decreasing lordosis at the L4-5 and L5-S1 levels. In the case of lower lumbar fusion, hyperflexion is expected at the adjacent segment when sitting on the floor. To avoid this, sitting with a lordotic lumbar curve is important. Surgeons should remember to create sufficient lordosis when performing lower lumbar fusion surgery in patients with an oriental life style.

Keyword

Lumbar lordosis; Floor-sitting; Chair-sitting; Segmental lordosis

MeSH Terms

Animals
Female
Floors and Floorcoverings
Humans
Life Style
Lordosis
Male
Spine

Figure

• 

  Fig. 1 A 34-year-old male participant's lateral radiographs of the lumbar spine obtained when standing (A), sitting on a chair (B), and sitting on the floor (C). In the standing position, whole lumbar lordosis (WL) is -66°, and segmental lordosis (SL) at the L5-S1, L4-5, L3-4, L2-3, and L1-2 levels is -22°, -14°, -10°, -6°, and -14°, respectively. When sitting on a chair, WL is -47°, and SL at the L5-S1, L4-5, L3-4, L2-3, and L1-2 levels is -9°, -5°, -9°, -7°, and -17°, respectively. When sitting on the floor, WL is -23°, and SL at the L5-S1, L4-5, L3-4, L2-3, and L1-2 levels is -6°, -3°, -1°, -1°, and -12°, respectively.

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