There is no simple diagnostic test for piriformis syndrome causing irritation of the sciatic nerve. The condition is primarily diagnosed on the basis of the patient’s symptoms and on a physical exam, and after excluding other possible causes of the patient’s pain.
Symptoms of Piriformis Syndrome
Most commonly, patients describe acute tenderness in the buttock and sciatica-like pain down the back of the thigh, calf and foot. Typical piriformis syndrome symptoms may include:
- A dull ache in the buttock
- Pain down the back of the thigh, calf and foot (sciatica)
- Pain when walking up stairs or inclines
- Increased pain after prolonged sitting
- Reduced range of motion of the hip joint
Symptoms of piriformis syndrome often become worse after prolonged sitting, walking or running, and may feel better after lying down on the back.
Diagnosing Piriformis Syndrome
Diagnosis of piriformis syndrome is based on a review of the patient’s medical history, a physical examination and possibly diagnostic tests.
Piriformis syndrome is often a diagnosis made through a process of ruling out other possible conditions that may be causing the patient’s symptoms, such as a lumbar disc herniation or sacroiliac joint dysfunction.
The physical exam will include an examination of the hip and legs to see if movement causes increased low back pain or lower extremity pain (sciatica pain).
Typically, motion of the hip will recreate the pain. The exam will also identify or rule out other possible causes of the sciatica pain, such as testing for local tenderness and muscle strength.
A medical history includes an in-depth review of the patient’s symptoms, such as what positions or activities make the symptoms better or worse, how long the symptoms have been present, if they started gradually or after an injury, and what treatments have been tried.
It will also include a review of conditions that may be in the patient’s family, such as arthritis.
X-rays and other spinal imaging studies cannot detect if the sciatic nerve is being irritated at the piriformis muscle. However, diagnostic tests (such as X-rays, MRI and nerve conduction tests) may be conducted to exclude other conditions that can cause similar symptoms to piriformis syndrome.
An injection of anesthetic with or without steroids may help to confirm if the piriformis muscle is the source of the symptoms.