- The piriformis muscle is a deep muscle located in the middle of the buttocks that can cause mechanical irritation of the sciatic nerve, resulting in piriformis syndrome.
- It may feel like local pain, but usually radiates to the back of the thigh and occasionally to the calf and heel. Usually, on true piriformis syndrome pain is more on lower part of buttock and leg.
- Symptoms are usually most pronounced during stretching and long term exertion as in longer distance hiking.
The piriformis muscle in the path of the sciatic nerve
The sciatic nerve runs from the lowback to the toes innervating whole lower extremity. The sciatic nerve passes under the piriformis muscle, but in some people, as a normal anatomical variation, it passes through or over it. Piriformis syndrome is caused by muscle tightness and shortening, which causes mechanical pressure and irritation of the sciatic nerve passing underneath.
Anatomy and function of the piriformis muscle
Anatomically, the piriformis muscle (m. piriformis) is one of the deep muscles of the buttocks. The muscle gets its name from the Latin word pirum, which describes the pear-shaped form of the muscle. For this reason, it is sometimes also referred to as the pear muscle. The muscle originates from the sacrum and attaches to the head of the femur, located fairly centrally in the buttocks. The main functions of the muscle are to rotate the leg outwards and to balance the position of the pelvis, for example when walking and running.
Symptoms of piriformis syndrome
People describe the symptoms of piriformis syndrome in many different ways. In principle, the symptoms are similar to those of a herniated disc in the lower spine, as both conditions irritate and press on the sciatic nerve, albeit in different places. In general, the symptoms of piriformis syndrome are milder and more variable, but may last longer than those of a herniated disc. In some people with similar symptoms, the symptoms may also be caused by hamstring syndrome, in which friction occurs at the upper attachment points of the hamstring muscles, but this is much less common than piriformis syndrome.
The most common symptoms are pain radiating to the back and side of the thigh, sometimes to the calf, the outer side of the lower leg, and the heel. Numbness, tingling, and other sensory changes may also occur in the same areas. Nighttime pain in the buttocks may also occur. The pain and other symptoms usually vary and are most commonly felt during and immediately after exercise. The discomfort can sometimes be relieved quickly by changing position and/or keeping the leg turned outwards and slightly bent. The muscle itself can also send trigger point-type radiating pain along the back of the thigh to the calf.
Causes of long term piriformis syndrome symptoms
Prolonged symptoms are usually caused by a combination of several factors rather than just one of the factors listed below.
- Non-structural / functional disorders, particularly in the lower back, buttocks, hip, knee, ankle, and foot on the same side.
- Anatomical variation in the course of the sciatic nerve under, over, or through the piriformis muscle.
- Excessive unilateral physical strain, such as endurance sports or excessive sitting.
- Psychological factors, such as anxiety, depression, and/or excessive mental strain, commonly known as stress.
- Lifestyle factors, such as too little or too one-sided exercise, insufficient or poor-quality sleep, and overweight.
- Central sensitization of pain system.
Treatment and rehabilitation of piriformis syndrome
Treatment and rehabilitation of piriformis syndrome are tailored to the individual and based on adequate diagnosis of the piriformis syndrome. Treatment usually includes manual therapy and individual exercises.
The stretches usually recommended for piriformis syndrome are generally not very effective, as the piriformis is one of the deeper gluteal muscles, making it rather questionable whether stretching the buttocks will target the muscle accurately. In piriformis problems, it is quite common that in cases without leg symptoms, other structures in the buttocks explain the symptoms and localised discomfort better than the piriformis muscle itself. The buttocks have many muscle layers, muscle attachment points, and various connective tissue structures, all of which can cause pain.
Read more about related pain syndromes:
Low back intervertebral disc problems
Hip flexor pain (Psoas syndrome)
Viimeksi päivitetty 13.10.2025
