ILIOPSOAS MUSCLE AND FASCIA ILIACA ⠀ [ANATOMY LESSON] ⠀ The iliopsoas muscle belongs to the inner hip muscles and is innervated by the femoral nerve + lumbar plexus. It consists of: ▪️Psoas major: origin. from 1st-4th lumbar vertebrae, costal processes of all lumbar vertebrae and 12th thoracic vertebrae + ins. at the lesser trochanter of the femur. ▪️Iliacus: runs from the iliac fossa to the lesser trochanter. The psoas major and iliacus unify in the lateral pelvis shortly before the inguinal ligament becoming the iliopsoas. There they pass below the inguinal ligament through the muscular lacuna together with the femoral nerve . Both muscles are completely surrounded by the iliac fascia . The lumbar plexus lies dorsally from the psoas major which is penetrated by the genitofemoral nerve. ⠀ The iliopsoas is the strongest flexor of the hip joint (important walking muscle). In the supine position it decisively supports the straightening of the upper body (e.g. during sit-ups). Furthermore it rotates the thigh laterally. A unilateral contraction leads to a lateral flexion of the lumbar vertebrae column. It plays a significant role in the movement and stabilization of the pelvis. ⠀ The majority of the body lies within the abdominopelvic cavity and is called the abdominopelvic or abdominal belly. When it passes deep to the inguinal ligament, it is the femoral belly. ⠀ How to palpate the psoas? Seeing the abdominal belly here informs our palpation protocol. First, we must contact the client immediately lateral to the rectus abdominis. But then, visualizing the muscle, we must sink in slowly posteromedially toward the spine. Once we feel the client’s spine deep to soft tissue, we should be on the psoas. So now we ask the client to gently engage it by flexing their thigh at the hip joint and we should feel the psoas palpably harden. Once located, we can now assess and treat if appropriate.