Which angle is associated with spondylolysis/spondylolisthesis when increased?

Which angle is associated with spondylolysis/spondylolisthesis when increased?

• A. Ferguson's angle
• B. Cobb angle
• C. Luschka angle
• D. Genu angle

Answer: (A)

An increased Ferguson angle signals forward slipping at the lumbosacral junction. Ferguson's angle, or the lumbosacral angle, is measured on a lateral lumbar radiograph as the angle between the horizontal line and the superior endplate of S1 (the base of the sacrum). When spondylolisthesis occurs, the vertebra (usually L5) slides forward on S1, causing the sacrum to tilt more anteriorly relative to the lumbar spine. That forward tilt increases the lumbosacral/Ferguson angle, so this angle becomes larger in spondylolisthesis. The other angles relate to different conditions: the Cobb angle is used for scoliosis or sagittal-plane curvatures of the spine, the Luschka angle isn’t a standard measure for this condition, and genu angle concerns knee alignment rather than the lumbar region.

An increased Ferguson angle signals forward slipping at the lumbosacral junction. Ferguson's angle, or the lumbosacral angle, is measured on a lateral lumbar radiograph as the angle between the horizontal line and the superior endplate of S1 (the base of the sacrum). When spondylolisthesis occurs, the vertebra (usually L5) slides forward on S1, causing the sacrum to tilt more anteriorly relative to the lumbar spine. That forward tilt increases the lumbosacral/Ferguson angle, so this angle becomes larger in spondylolisthesis.

The other angles relate to different conditions: the Cobb angle is used for scoliosis or sagittal-plane curvatures of the spine, the Luschka angle isn’t a standard measure for this condition, and genu angle concerns knee alignment rather than the lumbar region.