Piriformis syndrome is a condition that occurs when a small muscle deep in your buttock presses on the sciatic nerve, causing pain, tingling, or numbness that can radiate down your leg. Though relatively uncommon, it can significantly disrupt daily activities, from sitting at your desk to climbing stairs, and is sometimes mistaken for other back problems.

How Common Is Piriformis Syndrome?

Piriformis syndrome is not a very common condition. Research indicates that it accounts for only about 0.3% to 6% of all cases of lower back pain^[1]. Some estimates suggest that approximately 5% of people experiencing sciatica-like symptoms actually have piriformis syndrome rather than other spinal problems^[13]. While the condition is considered relatively rare overall, with roughly 200,000 cases diagnosed each year in the United States, it often goes unrecognized or misdiagnosed because it can mimic symptoms of other conditions^[11].

Interestingly, this condition appears to affect women more frequently than men, though researchers have not yet determined why this gender difference exists^[2][13]. The true number of people affected may be higher than reported because piriformis syndrome often goes undiagnosed or is confused with other conditions that cause similar pain patterns.

Understanding the Anatomy Behind the Problem

To understand piriformis syndrome, it helps to know a bit about the body parts involved. The piriformis muscle is a flat, narrow muscle located deep in your buttock region^[1]. This muscle runs from your lower spine through your buttock area to the top of your thighbone. Your piriformis muscle exists on both sides of your body and plays an important role in almost every movement your lower body makes^[1]. It helps with rotating your hip and turning your leg and foot outward^[7].

The sciatic nerve is the longest and largest nerve in your entire body. It starts at your spinal cord, travels through your buttocks, and continues down the back of each leg all the way to your feet^[1]. In most people—more than 80% of the population—the sciatic nerve runs directly beneath the piriformis muscle^[3]. However, some people are born with variations in their anatomy where the nerve passes through the muscle itself or even above it^[4]. These individuals are naturally more susceptible to developing piriformis syndrome.

The close proximity between the piriformis muscle and the sciatic nerve is precisely why trouble can develop. When the muscle becomes irritated, swollen, or goes into spasm, it can press against the nerve that lies so close to it^[2]. This pressure on the nerve is what causes the painful symptoms that people with piriformis syndrome experience.

What Causes Piriformis Syndrome?

Piriformis syndrome develops when anything causes the piriformis muscle to press on the sciatic nerve. The most common underlying causes include inflammation or swelling in the piriformis muscle or the tissues surrounding it, muscle spasms in the piriformis, and scarring within the muscle tissue^[1].

Several situations and activities can trigger these problems. Trauma to the hip, buttock, or leg area—such as injuries from falls or car accidents—can damage the muscle and lead to inflammation^[3][7]. Lifting something improperly or using poor body mechanics can strain or damage the piriformis muscle^[1]. Even something as simple as suddenly twisting your hip in an awkward way can cause injury^[2].

Physical activity patterns also play a significant role. Overexercising or performing repetitive motions, particularly long-distance running, can stress the piriformis muscle beyond its capacity^[1]. Athletes who engage in activities requiring significant hip rotation or who are going through periods of increased training intensity, such as pre-season conditioning or increased weightlifting, may develop muscle hypertrophy that contributes to the condition^[3]. Marathon runners and cyclists are particularly at risk^[11].

On the opposite end of the activity spectrum, a sedentary lifestyle can also cause problems. Having tight muscles from a lack of physical activity makes you more vulnerable to piriformis syndrome^[1]. Sitting for prolonged periods is a major contributor—this includes taxi drivers, office workers, truck drivers, and bicycle riders who spend long hours in seated positions^[3][9]. Even carrying a thick wallet in your back pocket directly behind the piriformis muscle can put enough pressure on it to cause problems over time^[13].

Some people develop what healthcare providers call primary piriformis syndrome, which results from abnormal anatomy present from birth. This can include being born with a sciatic nerve that takes an unusual path through the body, an abnormally formed piriformis muscle, or a bipartite piriformis muscle, which means the muscle is split into two parts^[1][3]. Other anatomical issues that can contribute include abnormal spine alignment such as scoliosis, having legs of different lengths, or foot problems^[13].

Who Is at Higher Risk?

Certain groups of people are more likely to develop piriformis syndrome based on their activities and lifestyle factors. Athletes involved in specific sports appear to be at elevated risk. Skiers, tennis players, and long-distance runners or cyclists face higher chances of developing the condition because these activities place repetitive stress on the piriformis muscle^[18].

Occupation plays a significant role as well. People whose jobs require prolonged sitting are particularly vulnerable. This includes truck drivers, taxi drivers, and office workers who spend most of their day seated^[3][9]. The sustained pressure on the piriformis muscle during extended sitting periods can lead to irritation, tightness, and eventually compression of the sciatic nerve. Surprisingly, even carrying a wallet in your back pocket while sitting for long periods can contribute to developing this condition^[13].

People who have previously had hip surgery may also be at increased risk^[13]. The surgical procedure or the recovery process can sometimes affect the piriformis muscle or the surrounding tissues. Additionally, individuals with certain anatomical variations, such as differences in the way the sciatic nerve courses through the pelvic region or those born with unusual piriformis muscle structure, naturally face a higher likelihood of experiencing problems^[4].

Recognizing the Symptoms

The symptoms of piriformis syndrome typically center around the buttock area but often extend beyond it. Pain is the hallmark symptom, and people describe it in various ways. The discomfort might feel like aching, burning, numbness, tingling, or shooting sensations^[1]. Most commonly, patients experience a deep, dull ache in the buttock, though some describe it as acute tenderness^[7].

What makes piriformis syndrome particularly recognizable is how the pain often radiates. The discomfort typically travels from the buttock down the back of the thigh, into the calf, and sometimes all the way to the foot^[2][9]. This pattern of pain mimics sciatica, which is why piriformis syndrome is sometimes called a sciatica-like condition. Along with pain, you might experience numbness in the buttock area and tingling sensations that follow the distribution of the sciatic nerve^[3].

The pain doesn’t remain constant throughout the day—certain activities tend to make it worse. Sitting for long periods typically increases the discomfort significantly^[1][2]. As you continue sitting, the pain often grows progressively worse. Walking, running, or climbing stairs can also aggravate symptoms^[1][7]. Some people find that the pain intensifies during activities that require them to rotate their hip or when they attempt to squat^[4].

Interestingly, symptoms often improve when you lie down on your back^[7]. This position typically relieves the pressure on the piriformis muscle and the underlying sciatic nerve. The condition can affect just one side of your body or both sides simultaneously, though one-sided symptoms are more typical^[1][2].

Beyond pain and altered sensations, piriformis syndrome can cause functional limitations. You might have difficulty sitting comfortably, particularly putting weight on the buttock on the affected side^[2][13]. The reduced range of motion in your hip joint can interfere with daily activities^[7]. For some individuals, the pain becomes so severe that it significantly limits their ability to work or perform normal activities, essentially becoming disabling^[2].

How Piriformis Syndrome Affects Your Body

When you have piriformis syndrome, several changes occur in how your muscles and nerves function. The piriformis muscle, which normally helps stabilize your hip and assists with rotating your leg, becomes irritated or inflamed^[9]. This irritation can cause the muscle to swell or tighten from spasms. When the muscle swells or goes into spasm, it puts pressure on the sciatic nerve that runs just beneath it (or through it, in some people)^[2].

This pressure on the sciatic nerve leads to what doctors call nerve compression or sciatic nerve entrapment^[3]. The compressed nerve cannot function normally, which is why you experience abnormal sensations like tingling, numbness, and pain that radiates down your leg. The nerve compression occurs specifically at the level of the ischial tuberosity—the bony prominence you sit on^[3].

The condition creates a cycle of dysfunction. The muscle irritation leads to spasm, which causes more irritation and potentially more spasm. This cycle can also affect nearby structures. The tension and altered function in the piriformis muscle can influence your entire pelvic region, affecting pelvic stability and hip movement patterns^[20].

Functional changes in your movement patterns often develop as well. To avoid pain, you might unconsciously start walking with your thigh turned outward or develop a shortened stride length^[14]. These adaptations can create functional limb-length differences, even if your legs are actually the same length. Over time, these altered movement patterns can lead to additional muscle imbalances and joint dysfunction, particularly affecting your lower lumbar spine and sacroiliac joint^[14].

Preventing Piriformis Syndrome

While there is no guaranteed way to completely prevent piriformis syndrome, several strategies can significantly reduce your risk^[13]. Regular exercise helps maintain muscle strength and flexibility in the piriformis and surrounding muscles, making them less vulnerable to injury and strain^[2].

If you exercise or participate in sports, taking proper precautions is essential. Always warm up before physical activity and stretch properly afterward^[1]. When you increase your exercise intensity, do so gradually rather than suddenly jumping to a much higher level. If a particular activity causes pain, stop immediately—pushing through pain can lead to further injury^[2]. Allow yourself adequate rest until the pain resolves completely. For runners, avoiding uneven surfaces and hills can help prevent excessive stress on the piriformis muscle^[2].

Your daily habits matter tremendously. If your job requires prolonged sitting, make it a priority to get up and move around regularly. Avoid sitting for extended periods without breaks^[2][4]. Using a standing desk for part of your workday can help, or simply set a reminder to stand and walk around every 30 minutes or so^[4]. This practice not only helps prevent piriformis syndrome but also benefits your overall health.

Small changes can make a difference. Remove your wallet or other bulky items from your back pockets before sitting, as these can put direct pressure on the piriformis muscle^[13][15]. Use proper posture when sitting, standing, and driving—sit up straight and avoid slumping^[2]. When lifting objects, use correct body mechanics to avoid straining your piriformis and other muscles^[1].

For people who have already experienced piriformis syndrome, continuing with home exercises and stretching routines is important to prevent recurrence^[13]. If you have legs of different lengths, wearing a heel-lift in one shoe can help maintain proper alignment^[13]. Address any other contributing conditions, such as spinal arthritis or foot problems, with appropriate treatment. If vigorous exercise triggered your symptoms in the past, consider modifying your activities—for example, switching from running to swimming, which places less stress on the piriformis muscle^[13].

How Doctors Diagnose the Condition

Diagnosing piriformis syndrome can be challenging because there is no specific test that definitively confirms the condition^[1][13]. The diagnosis is primarily clinical, meaning it relies on your symptoms, medical history, and physical examination rather than laboratory tests or imaging^[3][9].

When you visit a healthcare provider, they will start by asking detailed questions about your symptoms and when they occur. They’ll want to know about your activity habits, work environment, and any injuries you may have had^[1][2]. Your medical history, including information about past injuries and existing health conditions, helps them understand potential contributing factors.

The physical examination is particularly important for diagnosing piriformis syndrome. Your healthcare provider will perform various movements and manipulations to identify what triggers your pain and what doesn’t^[1]. They will stretch, rotate, press, and move your hip, buttock, and leg in specific ways to see which positions or movements cause discomfort^[1][2]. Certain maneuvers that reproduce characteristic buttock and leg pain help point toward piriformis syndrome^[6].

Because other conditions can cause very similar symptoms, doctors often need to rule out alternative causes before confirming piriformis syndrome^[1]. This process of elimination is crucial. Conditions like a herniated disc, spinal stenosis, lumbar canal stenosis, disc inflammation, hip bursitis, sacroiliac joint dysfunction, and arthritis of the spine can all produce pain patterns that mimic piriformis syndrome^[3][9][13].

To exclude these other conditions, your doctor may order imaging studies. An MRI (magnetic resonance imaging) scan of your lumbar spine can help rule out problems like a herniated disc or spinal nerve compression^[2][4][5]. CT (computed tomography) scans may also be used. Sometimes healthcare providers use ultrasound imaging to actually visualize the piriformis muscle pressing on the sciatic nerve, which can help confirm the diagnosis^[4][6].

In some cases, your doctor might recommend nerve conduction studies to assess how well your nerves are functioning, though these are not specific for piriformis syndrome^[7]. The lack of a definitive diagnostic test means that reaching a correct diagnosis can take time and requires careful evaluation by an experienced healthcare provider.