Lumbar lordosis: Inward curvature of the lumbar spine in the low back, which is normal to a certain extent. Musculoskeletal disease or poor posture can cause the curve to be greater than usual.See also lordosis. SLIDESHOW Back Pain: 16 Back Pain Truths and Myths See Slideshow From Back Pain Resources Is Your Back Pain Ankylosing Spondylitis?Exercises for Ankylosing Spondylitis Featured Centers Good and Bad Foods for PsoriasisVideo: Getting Personal on Life With MS Health Solutions From Our Sponsors Shot-Free MS Treatment Your Child and COVID-19 References J. Larry Jameson, et al. Harrison's Principles of Medicine. McGraw-Hill Professional Publishing Published: July 23rd 2018; Edition: 20.