in the low or mid back, SI joint, hip, groin, thigh, knee, or any combination. The iliopsoas gets innervation from the L2-4 nerve roots of the lumbar plexus which also send branches to the superficial lumbar muscles. The femoral nerve passes through the muscle and innervates the quadriceps, pectineus, and sartorius muscles. It also comprises the intermediate femoral cutaneous and medial femoral cutaneous nerves which are responsible for sensation over the anterior and medial aspects of the thigh, medial shin, and arch of the foot nerves. The obturator nerve also passes through the muscle which is responsible for the sensory innervation of the skin of the medial aspect of the thigh and motor innervation of the adductor muscles of the lower extremity (external obturator, adductor longus, adductor brevis, adductor magnus, gracilis) and sometimes the pectineus. Any of these innervated structures can be affected. Bleeding Iliopsoas muscle is a common site of bleeding in patients who are undergoing blood anticoagulation. Additional images See also Psoas abscess Iliopsoas tendonitis Muscles of the hip Dr. Ronald Conger References External links Hip flexors Iliopsoas muscles Muscles of the lower limb