What effects does the quadratus lumborum have on the spine? On the pelvis? On the rib cage?

• A. It depresses the ipsilateral rib cage.
• B. It extends, sidebends, and contralaterally rotates the spine; in rotating the spine and pelvis, it anteriorly tilts the ipsilateral hemipelvis.
• C. It flexes the spine and ipsilaterally tilts the pelvis.
• D. It has no effect on the rib cage.

Answer: (B)