Medically reviewed by Kashif J. Piracha, MD Key Takeaways The iliopsoas muscle is the major flexor of the hip joint, made up of the iliacus and psoas major muscles.Pain in the iliopsoas muscle can be ...

The shoulder muscles are responsible for maintaining the widest range of motion of any joint in your body. This flexibility is also what makes the shoulder prone to instability and injury. Muscles, ...