Clinical assessment of lumbar mobility: Height of the lumbar spine and localization of L1 by ultrasound.

BackgroundVarious tools for clinical assessment of lumbar mobility in the sagittal plane coexist. Their validity has been called into question in particular because of their fixed distances between their skin markers whatever the height of the subject.ObjectiveTo measure the distance between the lower margin of the Postero Superior Iliac Spines (PSIS) and the middle of the L1 spinous process and to analyze the characteristics that influence it. To check whether these new skin marks could be more reliable for developing a new clinical assessment tool for lumbar mobility.MethodThe distance between the lower margin of the PSIS and the L1, located by ultrasound, was taken in the standing position and analyzed on 200 participants.ResultsThe mean PSIS-L1 distance was 13.3 ± 1.8 cm, influenced mainly by standing height. A ratio or the regression line equation, based on the relationship between standing height and PSIS-L1, were highlighted.ConclusionsThe actual mode of placement of skin markers for the clinical assessment tools to evaluate lumbar mobility is not valid. The PSIS-L1/standing height ratio or the regression equation are the most effective ways for predicting the location of the upper skin marker (L1) for developing a new tool.