Lower crossed syndrome is a postural condition in which the rib cage drops and the pelvis tilts abnormally putting increased strain on the lower back and sacroiliac (SI) joints.  It can also lead to abnormal posture in the mid back and neck as well. Since the lower back and pelvis is the foundation of your posture, it is critical to ensure that you are not developing lower crossed syndrome.  It is becoming more and more common, especially as people are sitting more and more for work. Lower Crossed Syndrome is when the rib cage drops due to muscle imbalance, and maintaining lower body posture becomes extremely difficult, especially for long periods of time.