Ultrasound imaging of lumbar multifidus muscle: normal reference ranges for measurements and practical guidance on the technique

This cross-sectional. prospective study aimed to produce normal reference data for measurements of the lumbar multifidus; muscle. A total of 120 subjects. 68 females (aged 20 64 years) and 52 males (20 69 years) were studied. Bilateral transverse ultrasound images were made of multifidus at the fourth and fifth lumbar vertebrae (L4 & L5). Cross-sectional area CSA. cm(2)) and linear dimensions (AP, anteroposterior: Lat. lateral) Acre measured and the latter expressed a,, a ratio (AP Lat) it) reflect shape. Relationships between CSA and anthropometric measures were examined. Multifidus CSA was larger in males (P < 0.001) and age had no effect, The CSA was larger at L5 than L4 (P < 0.001) and highly correlated between the two levels (males r >= 0.82, females >= 0.80). Differences in Muscle shape were observed for gender. age and vertebral level. Between-side symmetry was high for size but not shape (CSA < 10% difference). Linear measurements Multiplied (AP x Lat) correlated highly with CSA (all groups r >= 0.94, P < 0.0001). The AP dimension was also acceptably predictive of CSA at L4 (r >= 0.79), There were no clinically useful correlations between CSA and anthropometric measures. These findings provide normal reference,, ranges for objective assessment of lumbar multifidus. This paper also addresses specific practical issues when scanning. multifidus. (c) 2004 Elsevier Ltd. All rights reserved.