Importance of the Psoas Muscle in Back Pain

Back pain is undoubtedly one of the most common medical conditions worldwide. Its incidence spans a vast number of races and geographical locations. Among the myriad of body parts that could possibly hurt an individual, headaches and back pain account for most of the reported cases. To a large extent, these have contributed immensely to significant morbidity and mortality, especially among chronic sufferers.

Back Pain

While headaches are quite common among every age group, there seems to be a misconception that back pain is pathognomonic of old age. Anyone can have back pain – you just need the right physical activity to make it happen, but then, nobody goes around seeking out activities that will hurt their back. Lower back pain, however, tends to be more common in females. So, if anyone can have back pain, what are the possible triggers?

Causes Of Back Pain

The human back is composed of several different structures working synergistically to bring about normal posture, help lift weight, and even augment movement efforts. These structures include bones, muscles, ligaments, tendons, intervertebral discs, and nerves. Any problem originating from any of the above-named structures can result in back pain. However, it is important to note that a percentage of back pain cannot be accounted for by damage to any of the above-named structures. The causes of backache include, but are not limited t,o the following:

Strain Injuries

Muscle spasms
Strained ligaments
Strained muscles

Strain injuries are commonly attributed to strenuous actions like heavy lifting, abrupt, uncoordinated movements, improper postures while carrying a heavy load, etc. These cause a significant stretch to the complex structures of the back, resulting in an ache. The commonest muscle implicated in these strain injuries to the back is the Psoas.

Structural Problems Arising From Disease States

Several disease conditions cause alterations in the structural integrity of the back muscles, tendons, discs, and ligaments. These include:

Osteoarthritis: This is the inflammation of bones with concomitant damage. It affects the bones of the spine and hips, and those of other body parts.
Osteoporosis: This is commonly seen in postmenopausal women and results from the withdrawal of the hormone estrogen after menopause. It causes a reduction in bone density, making them at an increased risk of pathological fractures. It can affect the bones of the vertebral column, hips, and long bones of the leg and arm.
Bulging Discs or Herniation of Discs: A displacement of the intervertebral discs can result in a backache. This arises from the increased pressure on the nerves exiting the spinal cord by the herniated disc.
Rupture of Intervertebral Discs: The intervertebral discs serve a cushioning function between two vertebral bones. When this cushioning effect is removed by the rupture of a disc, increased friction over the adjoining surfaces of the vertebral bones and the increased pressure on the exiting nerves from the spinal cord result in severe pain.
Kidney Abnormalities: Notably, kidney stones are a major cause of disabling back pain. Another renal cause of backache is an infection of the kidney(s) – a condition known as pyelonephritis.
An Abnormally Curved Spinal Column: This is one of the debilitating causes of chronic backache. Conditions like scoliosis, kyphosis, and lordosis are known to account for the significant discomfort arising from backache in sufferers.
Cancer of the Spine: primary or secondary (spreading from other organs to the spine), cancers of the spine result in back pain. These aches can arise from either the invasion of nerve fibers exiting the spinal cord or osteolytic (degeneration of bone mass) action on bones, making them more prone to fractures.
Pelvic Inflammatory Disease: This condition is most common in females. It arises from the infection of the pelvic structure,s including the cervix, uterus, fallopian tubes, and ovaries.
Reactivated Herpes Zoster – Shingles: Herpes Zoster infection (causing chickenpox), when treated, can undergo a dormant stage in the nerve fibers. These dormant viruses can be reactivated in the future by a case of malnutrition or immunosuppression. When reactivated, a condition known as shingles arises. The pain of shingles is distributed along the course of the nerve fiber in which the virus resides – hence, back pain when it affects the nerves of the back.
Cauda Equina Syndrome: This serious neurologic disease state arises from damage to a region of the spinal cord known as the Cauda Equina, resulting in its loss of function. This loss of function is attributed to the disruption of the lumbar plexus of the spinal cord. This syndrome causes debilitating back pain.
Disorders of Sleep: Research has shown that people with serious disorders of sleep are at an increased risk of developing back pain.

Despite the wide range of factors that have a causal relationship to fractures, some people are at an increased risk than others.

Risk Factors For Back Pain

A deskbound lifestyle
Older age
Occupational type
Bad sleeping and reading postures
Standing or sitting for long durations
Pregnancy and a large number of births
Poor physical activity
Heredity
Obesity
Smoking
Strenuous physical activities
Comorbid health conditions like arthritis, scoliosis, and cancer.

Role of the PSOA Muscle In Lower Back Pain

We talked about the role played by muscle strains in back pain. The role of one muscle cannot, however, be overemphasized – the Psoas (pronounced So-as).

What is the Psoas muscle?

Psoas Major. Image Courtesy of Anatomography

The Psoas muscle is a muscle of the lower back, finding attachment at the bones of the spine above and the femur of the leg below. They are in the posterior aspect of the abdomen, with the intestines and kidneys lying over them. It is a very broad piece of muscle that works synergistically with the Iliacus muscles (another muscle of the lower back with attachments at the spine above and the femur below) to bring about the stabilization of the spine and movements of the lower limb – they are the major muscles bringing about thigh flexion. The normal tension of the Iliopsoas (a combination of the two muscles) helps maintain normal posture. In fact, the professionals behind elitekearney.com state that if you can jog, jiggle a bit on the dance floor, or even get out of bed, it is time to give your Psoas a high-five. Doing so will help this muscle feel and perform better.

How does the Psoas Cause Pain?

Being the major flexors of the hip, the work of lifting the thighs lies on these incredibly strong groups of muscles. Hence, a unilateral or bilateral weakness of the Psoas will put outrageous stress on the other muscles of the lower back, resulting in back pain. Below is a list of several ways in which the Psoas muscle can result in back pain:

The strain of the Psoas.
Psoas weakness causes increased work on other back muscles.
Crush injuries to the Psoas.
Prolonged sitting, as in long journeys.
A Tight Psoas or tension over the Psoas muscle is also known as Psoas Myotonia.
Abscess in the abdominal cavity over the Psoas muscle. This accounts for some of the lower back pain associated with pelvic inflammatory diseases.

The above list is not exhaustive, but accounts for most of the Psoas-mediated back pain.

Symptoms Of Back Pain

The most recurring symptom of back pain is an ache or pain anywhere in the back, sometimes extending to the lower limbs, buttocks, and perineum. However, as discussed above, depending on the cause of the pain, other symptoms may be present. These may include weakness, urinary, and fecal incontinence, weight loss, etc.

Who is more at risk of backaches?

Females, the elderly, and those involved in strenuous physical activities.

When should you see a Doctor?

Medical help should be sought whenever back pain occurs following a fall or an injury, does not relieve with rest, is accompanied by weakness, fever, or unexplained weight loss, and numbness in the lower limbs.

Diagnosis Of Back Pain

When you visit your doctor, he will pose several questions to you with the aim of ascertaining the underlying cause of the ache. After these questions, he will most likely ask you to undergo some imaging modalities to confirm his suspicions. These imaging modalities may include an X-ray, Magnetic Resonance Imaging (MRI), Computed Tomography Scan (CT Scan), Bone Scans, and Electromyography(EMG).

After the above, he will devise a treatment pattern better targeted at the pain and underlying pathology.

Treatment

Most backaches are expected to resolve with rest and over-the-counter (OTC) medications. Resting after strenuous activity or a little stretch following stiffness can ease back pain. Also, the use of ice packs or hot compresses has proven helpful in the management of mild to moderate back pain. Non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen and naproxen have also proven to be quite effective.

When the above home remedies fail, and you visit your doctor, other drugs and modalities of treatment may be employed to manage the pain. Prescription drugs like Codeine and hydrocodone may be prescribed. They require expert supervision as they pose addictive threats. Other drugs include antidepressants, Botox, and Cortisone injections. Other treatment modalities include:

Use of traction devices
Cognitive-behavioral therapy
Transcutaneous electrical nerve stimulation
Surgery

Several other techniques have been employed in managing back pain. These include yoga, Shiatsu, and acupuncture.

Back pain is a major health concern, accounting for a great number of health burdens. The pathology underlying most lower backaches directly or indirectly involves the Psoas muscle. Avoiding strenuous physical activity, a good exercise routine, and early visits to a doctor in the event of back pain will result in a decline in morbidity.

References

Cleveland Clinic. (n.d.). Psoas syndrome: Symptoms, causes & treatment. Retrieved April 19, 2025, from https://my.clevelandclinic.org/health/diseases/15721-psoas-syndrome

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