What is the insertion point of the quadratus lumborum?

The quadratus lumborum is a significant muscle located in the lower back, and its primary insertion point is the medial half of the inferior border of the 12th rib. This insertion allows the quadratus lumborum to play a crucial role in stabilizing the lumbar spine and assisting with lateral flexion of the trunk.

By anchoring to the rib, the muscle can effectively contribute to movements such as bending to the side and elevating the hip on one side, which is critical for maintaining balance and proper posture. The connection to the 12th rib also illustrates how the quadratus lumborum influences respiratory mechanics, as it can impact the position and movement of the rib cage during breathing.

Other options suggest different insertion points that do not align with the anatomy of the quadratus lumborum. Recognizing its correct insertion is important for understanding its function and the biomechanics of the lumbar region.