During supine assessment of a patient with low back pain, increased lumbar lordosis occurs when one knee is brought to the chest. Which condition contributes to these presentations?

In the scenario presented, the increased lumbar lordosis when bringing one knee to the chest is primarily influenced by the condition of an iliopsoas contracture in the straight leg. The iliopsoas is a major hip flexor that plays a crucial role in stabilizing the pelvis and lumbar spine. When the iliopsoas is contracted or tight, it can prevent proper positioning of the pelvis and lumbar spine during movement and positioning.

As one knee is drawn toward the chest, if the other leg remains straight and the iliopsoas is contracted, it can create a posterior pelvic tilt on that side, which subsequently increases the lumbar lordosis. This results in an anterior tilt of the pelvis and emphasizes the natural curve of the lumbar spine, leading to increased lordosis in the supine position.

Understanding the mechanics of how the iliopsoas interacts with the lumbar spine is critical for assessing low back pain and determining the underlying contributors to altered spinal alignment during movement. This highlights the importance of evaluating muscle flexibility and strength in the context of low back pain assessment.