You have pain in your buttock. It’s a deep, dull ache, sometimes traveling down your thigh. You’ve had an MRI—it’s normal. Your doctor can't find anything obvious. People talk about sciatica, but the usual treatments don't change anything.

There is a strong chance your problem comes from a muscle most people have never heard of: the piriformis muscle.

Piriformis syndrome is one of the most frequent and most misdiagnosed causes of pain in France. It is estimated to be responsible for about 6% of sciatica-type pain—but this figure is likely underestimated, as conventional imaging tests do not detect it.

In this article, we explain what it is, how to recognize it, and above all, how to relieve it effectively.

---

1. What is the piriformis muscle?

The piriformis is a small, deep, pear-shaped muscle (hence its name, from the Latin pirum: pear) located in the buttock. It connects the sacrum—the triangular bone at the base of the spine—to the greater trochanter, the bony bump you feel on the side of your hip.

Its role is to rotate the leg outward and stabilize the hip joint while walking.

What makes it unique—and problematic—is its anatomical relationship with the sciatic nerve.

In 85% of the population, the sciatic nerve passes just below the piriformis. In the remaining 15%, it passes through the muscle itself—which makes these individuals even more vulnerable to piriformis syndrome.

When the piriformis contracts excessively, becomes inflamed, or spasms, it mechanically compresses the sciatic nerve. The result: pain identical to true spinal sciatica—but without any disc herniation visible on an MRI.

---

2. Piriformis syndrome or true sciatica: how to tell the difference?

This is the central question. Both conditions cause similar pain, but they have neither the same origin nor the same treatment. Confusing the two risks weeks of ineffective treatment.

Here are the key differences to observe:

Piriformis syndrome is characterized by:

• Pain deep in the buttock, on one side, sometimes described as an "internal" pain that is hard to locate precisely
• A clear worsening when sitting for long periods—in the car, at the office, or on a hard seat
• Partial relief when standing up and walking
• Pain that moves toward the sacrum as much as it travels down the thigh
• Sensitivity to touch in the buttock, halfway between the sacrum and the hip
• Pain worsened when crossing your legs or turning your thigh inward

True spinal sciatica is characterized by:

• Pain that clearly starts from the lower back
• Tingling or numbness that travels down to the foot along a specific path (L4, L5, or S1)
• Worsening when coughing or sneezing
• A disc herniation or stenosis visible on an MRI

---

3. The home test to identify the piriformis

This test is called the FAIR test (Flexion-Adduction-Internal Rotation). It is used by physical therapists to confirm the involvement of the piriformis.

How to do the FAIR test:

1. Lie on your back with your legs straight
2. Flex the painful leg to 90° (knee pointing toward the ceiling)
3. Cross this knee inward, over the other leg
4. Hold for 30 to 60 seconds

Interpretation: If this position reproduces or worsens your usual buttock or thigh pain, piriformis syndrome is likely. This test does not replace a medical diagnosis, but it is a useful indicator.

---

4. Causes of piriformis syndrome

Understanding why the piriformis contracts is essential to prevent relapses.

The 5 main causes:

1. Prolonged sitting: This is by far the most frequent cause. When sitting, the piriformis is constantly stretched. Over 6 to 8 hours a day, it accumulates micro-tension and ends up contracting permanently to "protect" itself. Remote work has increased cases since 2020.

2. Intense sports activity: Running, CrossFit, cycling, hiking on steep terrain—any effort that heavily engages the glutes can cause a piriformis spasm. Runners are particularly affected, especially on inclines or uneven terrain.

3. Pregnancy: Pregnancy hormones (notably relaxin) loosen pelvic ligaments. The piriformis then compensates for this lack of stability by contracting further. This is one reason why "pregnancy sciatica" is often actually piriformis syndrome.

4. Prolonged driving: The driver's position combines the two worst factors: a flexed sitting position AND slight rotation of the right hip (pedals). Professional drivers (rideshare, truckers, sales representatives) are very exposed.

5. Gait issues: Excessive foot pronation (foot collapsing inward) forces the piriformis to work constantly to stabilize hip rotation. Orthopedic insoles often partially correct the problem.

---

5. The 6 typical symptoms of piriformis syndrome

Here is the list of the most frequently reported symptoms by patients:

1. Deep pain in the buttock, on one side (rarely both)
2. Pain worsened by sitting for more than 20–30 minutes—the famous "stabbing" feeling when you stand up
3. Radiation toward the thigh, sometimes to the knee, rarely lower
4. Painful sensitivity to touch in the middle of the buttock (Jones point)
5. Pain when climbing stairs or when crossing your legs
6. Temporary relief while walking, then return of pain after a few minutes of standing

This last point often distinguishes the piriformis from spinal stenosis (which is relieved by sitting).

---

6. The 5 stretching exercises that really provide relief

These exercises directly target the piriformis. They are practiced in physical therapy and adapted for daily home practice.

Exercise 1—The modified pigeon (the most effective)

Lie on your back. Cross the ankle of the painful leg over the opposite knee. Grab the back of the opposite thigh and pull gently toward you. You should feel a deep stretch in the buttock. 30 to 45 seconds, 3 times, twice a day.

Exercise 2—The seated stretch (doable at the office)

Sitting on a chair, place the ankle of the painful leg on your opposite knee. Keep your back straight and lean forward slightly until you feel the stretch in the buttock. 30 seconds, 3 times. This exercise can be done discreetly at the office between meetings.

Exercise 3—The half-bridge with external rotation

Lie on your back, knees flexed at 90°. Lift your pelvis slightly, then let the knee of the painful leg fall outward. Hold for 20 seconds, then return. 5 slow repetitions. This exercise combines stretching and light strengthening.

Exercise 4—The partial sumo squat

Standing, feet apart (slightly wider than shoulders), toes pointed outward at 45°. Slowly descend into a half-squat (30–40 cm), hold for 20 seconds, and return to standing. 5 repetitions. The piriformis stretches naturally in this position.

Exercise 5—The duck walk

Squatting, feet flat, move forward while keeping the low position for 5 to 10 meters. Slow and controlled movement. 2 back-and-forth laps. A more advanced exercise—to be integrated after symptoms improve, to prevent relapse.

---

7. What heat does for the contracted piriformis

The piriformis is a deep muscle. Conventional pain relievers (ibuprofen, paracetamol) have little effect on this type of chronic muscle pain. Heat, however, penetrates to the deep layers and acts directly on the spasm.

Red light: where heat alone is not enough. The piriformis is a deep muscle—surface heat loses some of its effectiveness before reaching the deep fibers. Therapeutic red light penetrates up to 4–5 cm under the skin, reaching the contracted muscle directly. Combined with heat, it acts on two levels simultaneously: vascular at the surface, cellular at depth.

Here is what happens biologically:

1. Heat causes vasodilation of the blood vessels around the piriformis
2. Increased blood flow brings oxygen and removes accumulated metabolic waste (lactic acid, inflammatory prostaglandins)
3. The muscle receives the chemical signal to release the spasm
4. By relaxing, it stops compressing the sciatic nerve
5. Pain decreases, sometimes in a matter of minutes

The key: heat must be targeted (on the buttock and hip, not the lower back) and maintained over time (20 to 30 minutes minimum). A traditional hot water bottle slides, cools quickly, and offers no support. This is where a targeted thermal belt really makes a difference.

---

8. Complete treatment: the 3-phase protocol

Piriformis syndrome is not treated with a single action. It requires a combined approach over several weeks.

Phase 1—Weeks 1–2: Calming. Priority: reduce spasm and inflammation. Targeted heat 2 to 3 times a day, gentle stretching, reduction of sitting time. Avoid intense sports activities.

Phase 2—Weeks 3–4: Releasing and mobilizing. Progressively integrate all exercises. Add self-massage: use a tennis or massage ball placed under the buttock (while sitting on a chair), look for the painful point, and hold gentle pressure for 60 seconds. Resume daily walking for 20 to 30 minutes.

Phase 3—Weeks 5–8: Strengthening. Pain decreases but the muscle remains fragile. This is the most important phase to avoid relapse. Progressive strengthening of the glutes and core, posture correction at the office, resuming sports with support.

---

9. The role of support in treating the piriformis

Support plays a double role that is often underestimated:

• Mechanically: it reduces hip micro-movements that maintain the spasm
• Thermally: combined with a heat source, it diffuses and maintains the temperature on the target zone without you having to hold a hot water bottle

The difficulty with the piriformis is that it is located in the deep buttock—an area difficult to reach with conventional solutions (thermal patches, hot water bottles). A support that specifically targets the hip-buttock-sacrum area is far more effective than a simple lumbar belt that acts too high up.

---

10. FAQ—The most frequently asked questions about the piriformis

What exactly is piriformis syndrome? It is the compression of the sciatic nerve by the piriformis muscle—a deep buttock muscle—when it is contracted or inflamed. It is sometimes called "false sciatica" because the symptoms resemble spinal sciatica, but the origin is muscular, not disc-related.

How do I know if I have the piriformis syndrome rather than sciatica? The most distinctive sign: if your pain gets significantly worse while sitting and improves a bit when walking, the piriformis is likely. If your MRI is normal but you have sciatica-like pain, that is additional evidence. The FAIR test described in this article is a good indicator.

How long does the piriformis syndrome last? With appropriate treatment (stretching, heat, support, postural correction), the majority of cases improve in 4 to 8 weeks. Without treatment or with inappropriate treatment, it can become chronic and last for months.

Can the piriformis syndrome go away on its own? Rarely, if the cause is not corrected. As long as you sit 8 hours a day in the same posture, the muscle will continue to contract. Eliminating or modifying the cause (posture, sports activity, ergonomics) is essential.

Can I play sports with piriformis syndrome? In the acute phase: no. In the recovery phase: yes, gradually. Swimming and walking are recommended. Running, cycling, and sports with trunk rotation should be resumed very gradually after symptoms disappear.

Can a physical therapist treat the piriformis? Yes, and it is the reference treatment. Physical therapists use myofascial release techniques, passive stretching, neuromobilization, and targeted electrostimulation. Results are often rapid (2 to 4 sessions) if the diagnosis is correct.

Can the piriformis cause knee pain? Yes, in some cases. Compression of the sciatic nerve by the piriformis can radiate to the knee and even the calf, although the pain usually remains concentrated in the buttock and thigh.

Can an injection help for the piriformis? Yes. A corticosteroid or Botox injection directly into the piriformis muscle (under ultrasound guidance) may be offered in resistant cases. It does not resolve the root cause but provides a window of relief during which rehabilitation can be more effective.

---

In summary

Piriformis syndrome is a common cause of pain, often mistaken for classic sciatica. Its distinctive features — deep buttock pain, aggravation when sitting, and a normal MRI — make it relatively easy to suspect. Treatment is based on a combination of targeted stretching, therapeutic heat, support, and the correction of postural habits. Recovery is possible within a few weeks with the right approach.

---

This content is provided for informational purposes and does not replace medical advice. In case of severe or persistent pain, or pain accompanied by neurological symptoms, consult a doctor or physical therapist.