Psoas muscle: Great deceiver

One of the biggest factors in back and hip pain is frequently the psoas muscle.  

The number of potential problems caused by the psoas is surprisingly long and varied. This is due to the unusual shape, length and action of the psoas muscle. 

A dysfunctional psoas (pronounced so-az) muscle can contribute to the formation of: low back pain, hip pain, sciatica, disc problems, spine degeneration, scoliosis, hip degeneration, and knee pain. The list can also include biomechanical problems like pelvic tilt, hunching posture, and lumbar sway back. Athletes will notice loss of mobility, asymmetrical movement patterns and increase pain post-activity.  

It is the great number of problems associated with psoas muscle dysfunction that has lead to it being called the great deceiver. It is easy to be fooled as to where on your body the pain is actually being produced.  


Psoas anatomy 

The psoas primarily bends the hip to the body (like in climbing stairs) and flexes the torso (bending over to touch the toes). At about 16 inches long on the average, it is one of the largest and thickest muscles of the body (in animals it’s known as the tenderloin).  

This powerful muscle runs down the body from the bottom of the rib cage and connects to all the lumbar vertebral bodies, and discs. This lower portion combines with fibres from the iliacus muscle, a muscle which sits inside the surface of the pelvis and sacrum, to become the Iliopsoas muscle. “Iliopsoas” is quite a mouthful, so most people refer to the muscle just as the psoas or the hip flexor muscle. From the inside bowl of the pelvis the psoas attaches to the top of the leg at the inside of the groin.  

This incredible deep muscle attaches to the spine, the pelvis, and the leg – no other muscle attaches to all three major skeletal structures of the lower body.  


Psoas function  

The size, connections and area the of the psoas means it has quite a diverse set of functions. The psoas is a major walking muscle; it makes it possible to lift the legs. If the legs are stationary the action is to bend the spine forward; if sitting, it stabilises and balances the trunk. The lower psoas brings the lumbar vertebrae forward and downward to create pelvic tilt. 

When we think of smooth, elegant and graceful movement in dancers, we are looking at the psoas functioning at its optimum. The psoas keeps the pelvis positioned correctly and coordinates movement with the spine to require the least muscular effort. 

Someone who is performing a leg lift exercise is not exercising their abdominal muscles; they are contracting their psoas muscle! That deep burn felt in the abdomen is because the psoas is deep in the abdomen into the low back. 



When the muscle becomes contracted it can alter the biomechanics of the entire spine. A poorly functioning psoas muscle can affect all the muscles around it. There can be spasm and trigger points in other muscles in the low back, buttocks, hips and hamstring muscles.  

Classic symptoms of a psoas muscle spasm are a diffuse “ache” type low back pain. Usually a painful psoas muscle will cause referred pain down the front of the thigh and up the low back. The pain seems to spread to the rest of the low back and even into the buttocks and sides of the hips. It is difficult to stand upright quickly. Standing, walking and lying down don’t seem to affect it badly. Relief of pain is often experienced by sitting down. 

A tight psoas can twist and flex the spine creating some very unusual and painful postures. Often one psoas muscle will shorten more than the other creating a very clear distortion of the spine. This can result in scoliosis, hunching posture, sway back, and spasms in other back muscles trying to resist the pulling of the psoas. 


How does this happen 

The psoas usually becomes tight and contracted due to postural habits and trauma. The way we stand, walk and sit can all affect the psoas. Sitting for prolonged periods day after day causes the muscle to shorten into that position. Running and jumping sports can lead to a psoas injury. 

Even significant repetition of hip flexion (over-use injury) can cause shortness and tightness of the iliopsoas group. This can come in the form of cycling, stair climbing, or other exercise moves.  



Treatment of the psoas muscle is focused on restoring the normal flexibility and functional ability of this muscle group. Treatment will vary depending upon your history and presentation. Typically, treatment should include stretching, core strengthening, and resolution of whatever circumstances led to this problem in the first place. The psoas muscle is often treated with a broad based treatment plan that includes deep tissue massage, acupuncture, and cold laser. Your chiropractor will also address the functional issues that have been created in the pelvis, hips and low back.  


Dr. Jemal Khan is a chiropractor based in the Cayman Islands.