Diagnostic Ultrasound Imaging for Measurement of the Lumbar Multifidus Muscle in Normal Young Adults

Abstract

Real-time ultrasound imaging of the lumbar multifidus muscle was performed in 48 normal subjects (21 males, 27 females) aged 18-35 years. Measurements of multifidus cross-sectional area (CSA) and shape were symmetrical between the right and left sides of the spine. Muscle shape differed between the males and females. Two measurements (linear dimensions) of the muscle cross-section were closely correlated with CSA in both groups (males r=0.98; females r=0.93), but this relationship needs to be determined in wasted muscles where changes in shape may occur. Correlations between CSA and height and weight differed between males and females/Measurements were repeatable between days (CV = 6%) and between scans (CV = 4.9%). The present study indicates that real-time ultrasound may be clinically useful for measuring multifidus muscle wasting, but larger scale studies are required to establish definitive reference ranges of data in different age groups of normal subjects. Documentation of changes in symmetry of multifidus muscle size and shape with back pain could then be performed.