Articles
The Importance of the Psoas Muscle
The What and Where: Anatomically, the psoas (pronounced so-az) is a large muscle, measuring 16 inches in length and basically anchors your leg to your trunk. It lies deep to the spine and starts at the front of the spinal vertebra T12. It attaches along the respiratory diaphragm and lumbar vertebrae from L1 to L5. It meets up with the iliacus muscle of the pelvic bowl and dives under the groin to finally insert on the inner thighbone, thus influencing the movement and rotation of the pelvis.
Essentially, all the organs are in contact, either directly or indirectly, with the diaphragm and psoas. The heart sits on top of the diaphragm, while the stomach, liver, gallbladder, spleen and colon lie underneath it. The kidneys lay next to the outer edge of each psoas muscle and the ureters run parallel to it. The bladder and reproductive organs lie in front of the psoas. The abdominal aorta which provides blood flow to the pelvis and legs, runs through the abdominal cavity on the inner edge of each psoas.
Function: The psoas bends your hip and leg towards your chest when going up and down stairs and helps to propel the leg forward when walking or running. It flexes your trunk forward when squatting or bending over to pick up something from the floor. Fundamentally, it acts like a guide wire to stabilize the trunk and spine during movement and sitting. It correctly balances the abdominal and low back muscles ensuring erect posture. The psoas supports the internal organs and functions as a hydraulic pump. Its movement allows for fluids to be pushed in and out of cells, such as blood and lymph. When the fear reflex gets activated, the psoas flexes the hip. You see this in an infant when it becomes startled: the legs fly up towards its face instinctively to protect itself. As the child grows into adulthood, this reflex gets integrated. Instead of legs moving towards the face, now the trunk flexes toward the legs. During times of stress when you may be in self-protection mode, your psoas in under a state of constant contraction.
Impact of a shortened psoas: The length of the psoas determines whether the pelvis is free to move or not. It becomes shortened from prolonged sitting, excessive running/ walking, sleeping in the fetal position and even stress, as noted above. A shortened psoas muscles affects posture in the following ways:
1. The hips thrust forward creating rotation of the pelvis and an internal rotation of the affected leg. The opposite leg will rotate externally to counter-balance the asymmetry. To the body, the affected leg is now longer, and every time the person steps, it drives the leg up into the hip socket, creating further imbalance, leading to a functional leg length discrepancy.
2. The pelvis and thigh draw closer, thus limiting space and movement in the hip socket. In essence, the femoral head is locked into the socket and instead of rotation occurring at the hip joint; it produces a torque at the knee and at L4-L5.
3. Spinal segments compress, creating a lordotic posture of the low back and pelvis. The network of lumbar nerves and blood vessels passes through and around the psoas, so tightness here will impede the flow of blood and nerves impulses to the pelvic organs and legs, potentially affecting sexual and elimination functions and creating numbness and tingling in the legs and feet.
4. It’s responsible for menstrual cramps as it puts added pressure in the reproductive organs.
5. It creates a thrusting forward of the ribcage and encourages chest breathing, which limits the amount of oxygen taken in and encourages over usage of the neck muscles. The trunk shortens and the space for the internal organs is decreased, which affects food absorption and elimination, contribution to constipation.
Helping Yourself: Exercises such as prolonged walking or running, sit-ups and push-ups actually weaken the psoas by creating increased tension and shortening. Does that mean you can’t do these exercises? No, but be aware that to restore the normal length of the muscle, you need to stretch out the psoas. This can be achieved through specific psoas stretches. Most chairs or seats are not designed to support the body. Avoid bucket seats and chairs without support for the low back. Sit so your hips are level or slightly higher than your knees. Add support to your car seat with a rolled up towel underneath your sit bones and/ or behind your lumbar spine to keep the psoas and hip sockets released. If you sit for prolonged periods at a computer for your job, get up every hour and stretch for 60 seconds to get out of the position and promote blood flow. If you are traveling long distances, you should stop every 3 hours to stretch and walk around about 10 minutes. When you arrive home or at your final destination, get on your ball and do some stretches. Bodywork, stretching and yoga are excellent ways to restore balance to the body and maintain optimal health. HOPT offers wellness packages for those who have finished the therapeutic stage of their journey and want to maintain what they’ve achieved. I teach the basic Myofascial Stretching class, which introduces the concepts of myofascial stretching and incorporates general stretches to keep the fascial system fluid. Kristi McGrath instructs the Self Healing Class, which focuses more on releasing specific body parts, i.e. shoulder. Additionally, Kristi teaches a myofascial yoga class on Wednesday night. Traditional yoga classes are offered Tuesday and Thursday evenings. Check out our website for times. Please keep in mind all yoga classes are separate from HOPT, though they are held at our facility. Best of luck to you on your journey, whatever stage you are at.
Laura K. Holzworth, DPT
