Piriformis Muscle, Psoas Muscle, and Quadratus Lumborum Muscle Injections: Ultrasound

This chapter describes the anatomy, technique, available evidence, and complications of piriformis, psoas, and quadratus lumborum muscle injections. Traditionally landmark-based injections of the piriformis muscle were performed using the posterior inferior iliac spine and the greater trochanter as bony landmarks. Subsequently, fluoroscopy, electromyography, and CT were used to facilitate the injection. Activation of myofascial trigger points within the iliopsoas muscle can cause referred pain to the groin and anterior thigh. Landmark-based injections and CT-guided iliopsoas injections have been described. But they carry the risk of radiation, bowel injury, intravascular injection, and nerve injury. Ultrasound-guided injection into the psoas muscle may be performed at two different locations, the iliopsoas muscle and the iliopsoas tendon. The quadratus lumborum is a common cause of low back pain, and ultrasound-guided injection of local anesthetic into quadratus lumborum muscle may be performed.