The Relationship between Sagittal Curvature (Lumbar Lordosis) and Extensor Muscle Volume in Lumbar Region: A Morphological and Radiological Study

Abstract
Background: The vertebral column has a variable range of movements. It provides a load-carrying capacity that supports physical activities during daily life. The forces exerted by extensor muscles to stabilize the lumbar spines is related to its size which is affected by lumbar lordosis. The forces would be greater in cases of larger sagittal curvature (lordosis).
Aim of Study: Was to detect the relationship between extensor muscle volume and lumbar lordosis by using magnetic resonance imaging (MRI) of the lumber region and to Compare the results in subjects not complaining of low back pain with those presenting with low back pain. Findings could guide the physicians during training programs in the field of sports and rehabilitation.
Material and Methods: Two hundred subjects were clas-sified into two groups; group (A) representing individuals with no history of back pain and group (B) with history of low back pain (LBP). Magnetic resonance imaging (MRI) examinations of the lumbar spines were done for all cases. Axial and sagittal T1WI, T2WI and gradient images were done. The lower lumbar curvature was determined from sagittal images. The volume of the extensor muscles caudal to the mid-lumbar level was estimated in axial MRIs spanning the lumbar spine.
Results: Statistically significant positive correlation between the angle of lumbar curvature and muscle volume was found at all ages of group A (p=0.001) and group B-III (p=0.008). While no statistically significant correlation was detected in group B-I: p=0.089 and group B-II: p=0.061. The mean muscle volume in LBP subjects (group B) was signifi-cantly smaller than group A in all ages.
Conclusion: The magnitude of the lumbar lordosis present in a normal subject is related to the quantity of the extensor muscle and any deviation in the angle of the lumbar curvature or the size of the muscle by decreasing or increasing than normal could be the beginning of low back pain or a patho-logical condition.