The psoas muscle can be a source of pain that feels like it originates in the abdomen. This deep-seated muscle connects the spine to the leg and runs directly through the abdominal cavity. When the psoas is tight, strained, or inflamed, the resulting discomfort is often misinterpreted as stomach pain or a problem with the internal organs. This confusion arises because the muscle is situated close to major nerves and abdominal structures, causing muscle pain to be sensed in a different location than its actual source. Differentiating between muscular and visceral causes of discomfort begins with understanding the psoas’s anatomy.
Anatomy and Function of the Psoas
The psoas major is a long muscle located deep within the body, spanning from the lower back to the upper thigh. It originates from the transverse processes and vertebral bodies of the last thoracic vertebra (T12) down through the first four lumbar vertebrae (L1-L4). The muscle fibers merge with the iliacus muscle in the pelvis to form the powerful iliopsoas group, which inserts onto the lesser trochanter of the femur. The primary function of the psoas is to act as the strongest flexor of the hip joint, helping to lift the leg toward the torso during walking or running. It also plays a significant role in postural stabilization, helping to maintain the upright curve of the lower spine.
Why Psoas Issues Feel Like Stomach Pain
The anatomical position of the psoas explains why its dysfunction is often mistaken for abdominal or visceral pain. Running along the posterior abdominal wall, the muscle is situated directly behind the digestive organs. Inflammation or spasm in the psoas can physically irritate nearby structures, including the intestines and the lining of the abdominal cavity. The resulting pain is then perceived in the front of the body, mimicking stomach trouble.
Referred Pain
A more precise explanation involves the dense network of nerves that pass near or through the muscle. The lumbar plexus, which supplies the lower limbs and groin, is embedded within the psoas itself. When the psoas becomes tight or inflamed, it can compress or irritate these nerves, such as the genitofemoral and femoral nerves. This causes referred pain, where the brain interprets the signal as originating from areas like the anterior hip, groin, or lower abdomen.
When the muscle is strained, the pain often feels deep and vague, lacking the precision associated with surface-level muscular injuries. This poorly localized sensation is a hallmark of pain that mimics problems with internal organs. For instance, the right psoas muscle lies directly beneath the appendix, and irritation of this muscle is a standard diagnostic test for appendicitis.
Key Symptoms of Psoas Pain
Differentiating psoas pain from true visceral abdominal pain requires paying close attention to how the discomfort behaves in relation to movement. Psoas pain is often described as deep anterior hip or groin pain that can radiate into the thigh or lower back. Unlike stomach issues, this discomfort is typically unilateral, felt predominantly on one side of the body.
Movement-Related Discomfort
A defining characteristic is that the pain changes with activity or position. Individuals often report increased pain when attempting to stand fully upright or walk, as this requires the muscle to lengthen and stretch. The pain may also worsen when moving from a seated to a standing position. Conversely, the pain often lessens when the hip is flexed, such as when lying in the fetal position, which shortens the psoas muscle and relieves tension.
Postural changes may also be present due to a chronically tight psoas. This can manifest as an exaggerated inward curve of the lower back, known as increased lumbar lordosis, or a tendency to limp while walking. A medical sign known as the “psoas sign” involves pain when the hip is passively extended while lying on the side, confirming irritation of the muscle. Recognizing these movement-related symptoms is instrumental in identifying the psoas as the source of the lower abdominal discomfort.
Treatment and Relief Strategies
Managing psoas-related discomfort generally begins with conservative, non-surgical approaches focused on reducing tension and restoring muscle balance. Gentle stretching is a primary strategy for a tight psoas, with the kneeling hip flexor stretch being a common and effective technique. This involves kneeling on one knee and gently pushing the hips forward until a stretch is felt in the front of the hip on the kneeling side. These stretches should be performed consistently and without forcing the movement.
Rest and activity modification are also important initial steps, particularly avoiding repetitive hip flexion activities that may have caused the strain. Applying heat can help relax the tight muscle fibers and alleviate spasm, while cold therapy may be used to reduce acute inflammation. Strengthening exercises that focus on the core and gluteal muscles can help stabilize the pelvis and prevent future psoas overactivity.
It is important to seek professional medical attention if the abdominal pain is severe, accompanied by systemic symptoms like fever, or if the pain is constant regardless of position. Such symptoms could indicate a more serious condition, such as appendicitis or a psoas abscess, that requires immediate diagnosis and treatment. A healthcare provider can perform specific diagnostic tests to rule out these possibilities and create a tailored physical therapy plan.