If L5 is side bent right, where is the axis of the sacrum?

If L5 is side bent right, where is the axis of the sacrum?

• A. Left
• B. Neutral
• C. Right
• D. Superior

Answer: (C)

When a sacral issue involves an oblique axis, the lumbar spine motion—specifically how L5 side-bends—reflects which axis is guiding the sacrum. L5 will tend to side-bend toward the same side as the sacral oblique axis. So if L5 is side-bent to the right, the sacrum is rotating about the right oblique axis, placing the axis on the right. The left axis would produce left SB, a neutral pattern wouldn’t correspond to an oblique-axis sacral dysfunction, and a superior option isn’t used to describe sacral oblique axes. Therefore, the axis is on the right.

When a sacral issue involves an oblique axis, the lumbar spine motion—specifically how L5 side-bends—reflects which axis is guiding the sacrum. L5 will tend to side-bend toward the same side as the sacral oblique axis. So if L5 is side-bent to the right, the sacrum is rotating about the right oblique axis, placing the axis on the right. The left axis would produce left SB, a neutral pattern wouldn’t correspond to an oblique-axis sacral dysfunction, and a superior option isn’t used to describe sacral oblique axes. Therefore, the axis is on the right.