Psoas Major

Description

Running along the anterolateral lumbar spine, the psoas major is shown arising from the bodies, intervertebral discs, and transverse processes of the lower thoracic and lumbar vertebrae before descending inferiorly toward the pelvic brim. Medial to the iliacus on the internal surface of the ilium, its muscle belly crosses anterior to the sacroiliac region and passes deep to the inguinal region en route to the proximal femur. Distally, psoas major and iliacus converge to form the iliopsoas tendon, which inserts on the lesser trochanter and anterior aspect of the femur. Clear bilateral symmetry helps orient left versus right relationships against the sacrum and iliac fossae. Clinical relevance concentrates at the pelvic brim and anterior hip, where the iliopsoas traverses close to the femoral nerve, external iliac vessels, and anterior hip capsule, relationships that matter when evaluating anterior hip pain. Iliopsoas tendinopathy and internal snapping hip typically localize near the lesser trochanter or iliopectineal region, and this anatomy also explains why psoas abscess can track from lumbar infection into the groin. Short. For surgeons, the depiction supports planning for anterior approaches to the hip and for spine or pelvic procedures where psoas retraction risks lumbar plexus irritation. Use this illustration in gross anatomy and kinesiology teaching on hip flexors, in orthopedic and sports medicine publications discussing snapping hip and iliopsoas impingement, and in radiology education for correlating CT or MRI findings along the psoas compartment and iliopsoas tendon course. Anatomical accuracy verified by SciePro's Medical Advisory Board.