Iliopsoas

Clinical Notes

• The primary driver of conditions/lower-crossed-syndrome — chronic iliopsoas shortening pulls the pelvis into anterior tilt, increases lumbar lordosis, and reciprocally inhibits gluteus maximus. This is the most common postural dysfunction pattern in the sedentary population.
• Contributes to conditions/lumbar-disc-herniation — the vertical orientation of psoas along the lumbar spine means chronic hypertonicity increases compressive loading on the lumbar discs. Combined with the anterior tilt (which loads the posterior disc annulus), this creates the biomechanical setup for disc injury.
• Relevant to conditions/hip-flexor-strain — acute injury to the iliopsoas typically occurs during forceful hip extension (sprinting, kicking) and presents as sharp anterior hip or groin pain with resisted hip flexion.
• Psoas involvement in conditions/femoral-nerve-entrapment — the femoral nerve passes through the fibers of psoas major before emerging lateral to it. A chronically hypertonic psoas can compress the femoral nerve, producing anterior thigh pain and quadriceps weakness.

• In the majority of clients who sit for extended periods (desk workers, students, drivers), iliopsoas is shortened bilaterally. A positive Thomas test is one of the most common clinical findings in practice.
• Psoas is often hypertonic without the client being aware — they present with "low back pain" and do not recognize that the hip flexors are the source. The pain is in the back because the anterior pelvic tilt loads the posterior structures.
• Iliacus is frequently the more symptomatic of the two components, particularly at its attachment in the iliac fossa and near the inguinal ligament, but it is less commonly assessed because students are more familiar with psoas.

• Psoas responds to sustained compression but requires careful, slow access through the abdomen. The client must be relaxed — if they are guarding, you cannot reach the muscle. Knees bent, feet flat, verbal coaching to breathe and relax.
• Iliacus is more accessible via the iliac fossa and responds well to sustained pressure along the inner ilium. This is often less intimidating for both therapist and client than the abdominal psoas approach.
• Post-treatment stretching is essential — the Thomas test position (supine, one knee to chest, test leg hanging off the table) is both an assessment and a stretch. Active hip extension stretching after treatment extends the treatment effect.

• The abdominal aorta lies anterior to the lumbar spine, slightly left of midline. During psoas palpation, always check for a pulse before applying sustained pressure. If you feel a strong, rhythmic pulse, you are on or near the aorta — move laterally immediately.
• The femoral nerve emerges lateral to psoas. Sustained pressure lateral to the muscle belly at the level of the inguinal ligament can compress the nerve, producing anterior thigh numbness or quadriceps weakness. If the client reports these symptoms, reposition.
• Abdominal viscera — you are pressing through the intestines to reach psoas. In clients with inflammatory bowel conditions, recent abdominal surgery, or abdominal aortic aneurysm, abdominal psoas palpation is contraindicated.
• Inguinal region sensitivity — work near the inguinal ligament and groin requires clear communication and consent. Explain what you are doing and why before working in this area.

• Iliopsoas shortening is the initiating event in the lower crossed cascade: shortened hip flexors → anterior pelvic tilt → increased lumbar lordosis → compressed lumbar facets and posterior disc annulus → compensatory erector spinae hypertonicity → reciprocal gluteal inhibition. Addressing the iliopsoas is Step 1 in correcting lower crossed syndrome.

• When a client cannot activate their glutes on MMT despite adequate-looking gluteal tissue, release iliopsoas first, then immediately retest. Reciprocal inhibition from hypertonic hip flexors is the most common cause of gluteal inhibition — you can often restore full gluteal activation in a single session by addressing the iliopsoas, without ever touching the glutes directly.