Function & Connections: The Psoas


  • The psoas helps to stabilize the spine.
  • It provides support, “forming a shelf for the vital organs of the abdominal core” (Danielle Prohom Olson)
  • It is considered to be the most important hip flexor. The other hip flexors include the sartorius, the tensor fascia lata (TFL), the rectus femoris, the pectineus, and the adductor brevis.
  • From standing, hip flexors lift the leg to step up on a stool. From a supine position, the hip flexors lift a leg or lift the torso.


  • Due to its size and location, the psoas affects flexibility and posture.
  • The psoas is connected through fascia to the diaphragm, “which affects both our breath and fear reflex.” (Danielle Prohom Olson)
  • Related to the stress response, the psoas contracts involuntarily when the emotional state indicates stress.


The Wide-Ranging Impact of the Psoas Muscle

The psoas is interrelated to skeletal balance, flexibility, range of motion, joint rotation, organ functioning, breathing, circulation, adrenal health, nerve functioning, emotional stability and giving birth naturally. Additionally, working with the psoas helps to dismantle layers of tension and a multitude of muscular and skeletal compensations…

An essential aspect of the fight-flight-freeze response, the psoas expresses our innate sense of safety. The psoas is both an instinctive as well as an emotionally responsive muscle and by tuning into this muscle (without the use of invasive or manipulative approaches), we can gain a deeper sense of calm, integrity, and empowerment. – Liz Koch

The Psoas and The Stress Response

Part of the stress response hardwired into our nervous system is the contraction of the major flexors of the torso—somewhat like the response of a caterpillar if you poke it with a twig. A verbal jab from a co-worker, the close call on the freeway, a long-standing argument with your spouse, free-floating anxiety—all of these elicit a contraction in the flexors. This is the tightening in the gut, the hunching of the shoulders, the sinking of the heart. As with all responses to stress, the problem is that the response becomes habitual, resulting in chronic tension and contraction, which we then experience as our “normal” state. Our yoga practice is an opportunity to undo this chronic tension, and establish a deep and abiding sense of harmony in the body and mind. The psoas (so-as), an important flexor with an exotic name, is particularly sensitive to emotional states. – Sandra Anderson

In image below, the iliopsoas is in turquoise blue.