What is Piriformis Syndrome?
Piriformis syndrome is a condition in which the piriformis muscle, located in the buttock region, spasms and causes buttock pain. The piriformis muscle can also irritate the nearby sciatic nerve and cause pain, numbness and tingling along the back of the leg and into the foot (similar to sciatic pain).
The Piriformis Muscle
The piriformis muscle is a small muscle located deep in the buttock (behind the gluteus maximus).
The piriformis muscle:
- Starts at the lower spine and connects to the upper surface of each femur (thighbone)
- Functions to assist in rotating the hip and turning the leg and foot outward
- Runs diagonally, with the sciatic nerve running vertically directly beneath it (although in some people the nerve can run through the muscle).
Causes of Piriformis Syndrome
The exact causes of piriformis syndrome are unknown. Suspected causes include:
- Muscle spasm in the piriformis muscle, either because of irritation in the piriformis muscle itself, or irritation of a nearby structure such as the sacroiliac joint or hip
- Tightening of the muscle, in response to injury or spasm
- Swelling of the piriformis muscle, due to injury or spasm
- Bleeding in the area of the piriformis muscle.
Any one or combination of the above problems can affect the piriformis muscle (causing buttock pain) and may affect the adjacent sciatic nerve (causing pain, tingling, or numbness in the back of the thigh, calf, or foot).
A disorder in which the piriformis muscle in the buttocks irritates the sciatic nerve.
Symptoms include pain, tingling, or numbness in the buttocks and down the leg, which may worsen after sitting for a long time, climbing stairs, walking, or running.
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.
Almost every treatment approach for piriformis syndrome will include a focus on carefully and progressively stretching the piriformis muscle.
Stretches for Piriformis Syndrome
A number of stretching exercises for the piriformis, hamstrings and hip extensors may help decrease the painful symptoms along the sciatic nerve and return the patient’s range of motion.
There are a number of ways to stretch one’s piriformis muscle. Two simple ways include:
- Lie on the back with both feet flat on the floor and both knees bent. Pull the right knee up to the chest, grasp the knee with the left hand and pull it towards the left shoulder and hold the stretch. Repeat for each side.
- Lie on the back with both feet flat on the floor and both knees bent. Rest the ankle of the right leg over the knee of the left leg. Pull the left thigh toward the chest and hold the stretch. Repeat for each side.
Each piriformis stretch should be held for 5 seconds to start, and gradually increased to hold for 30 seconds, and repeated three times each day.
Stretching the hamstrings (the large muscle along the back of each thigh) is important to alleviate any type of sciatic pain. There are a number of ways to stretch the hamstrings:
- Place two chairs facing each other. Sit on one chair and place the heel of one leg on the other chair. Lean forward, bending at the hips until a gentle stretch along the back of the thigh is felt, and hold the stretch.
- Lie on the back with both legs straight. Pull one leg up and straighten by holding on to a towel that is wrapped behind the foot until a mild stretch along the back of the thigh is felt.
Again, try to work up to holding each stretch for 30 seconds and repeat three times each day.
Physical Therapy for Piriformis Syndrome
In addition to basic stretching, a comprehensive physical therapy and exercise program can be developed for each patient’s individual situation.
Range of motion exercises
A physical therapist, physiatrist, chiropractor or other qualified health practitioner can develop a customized program of stretching and range of motion exercises to help stretch the muscle and decrease spasm.
Deep massage (manual release) by a physical therapist or other qualified specialist is thought to enhance healing by increasing blood flow to the area and decreasing muscle spasm.
In addition to stretching and physical therapy, most treatment approaches for piriformis syndrome will include additional therapies, discussed on the next page.