Your hips are the bridge between your upper body and lower body. They are at the center of your body's movement. Sitting within the well of your hip and lower spine is the psoas major muscle, one of the two muscles that makes up the iliopsoas. It’s often called the "mighty" psoas (pronounced so-az) for the many important functions it plays in the movement of your body.
The psoas is the only muscle in the human body connecting the upper body to the lower body.
The muscle attaches to the vertebrae of the lower spine, moves through the pelvis and connects to a tendon at the top of the femur. It also attaches to the diaphragm, so it’s connected to your breathing, and upon it sits all the major organs. A functioning psoas muscle creates a neutral pelvic alignment, stabilizes the hips, supports the lower spine and abdomen, supports the organs in the pelvic and abdominal cavity and gives you greater mobility and core strength.