Piriformis Syndrome occurs when the sciatic nerve is compressed by the piriformis muscle.
The piriformis muscle is located under the gluteal (buttock) muscles and it is involved in almost all movements of the hip and leg. This muscle is attached to the sacrum and stretches out to the larger trochanter of the femur.
The sciatic nerve branches out from the lower spine and threads its way behind the hip joint and can either run alongside the piriformis muscle or sometimes go right through it. The sciatic nerve is the largest in the body, running along the back of the leg and to the foot.
Symptoms of Piriformis Syndrome may include:
- Tingling or numbness down the leg, sometimes to the foot
- Low back pain
- Pain associated with prolonged sitting and/or standing
- Increase in pain when moving from sitting to standing
- Deep pain in the hip or buttock
- Pain with hip flexion, adduction and internal rotation (squatting)
- Tightness or pain in the calf muscles and hamstrings
- Decreased range of movement of the hip
- SI (Sacroiliac Joint) instability
Piriformis Syndrome May be Relieved by:
- Application of heat and/or ice
- Yoga and stretches that reduce sciatic nerve compression
- Healthy posture
- Decrease exercises done on hills or uneven surfaces
There is an ongoing debate whether this is a rare or common issue, but we do know that one of the factors that can increase it is pregnancy.
Causes of Piriformis Syndrome may Include:
- Poor standing posture (pronation and flat-footedness)
- Not sitting equally on both sitz bones (sitting on a foot or wallet)
- Gardening (kneeling and bending movements)
- Prolonged sitting and/or driving
- Injury or tension
- Shortened hip flexors, causing anterior pelvic tilt
- Overuse of piriformis muscle (exercises that involve bending and lifting, squatting with heavy object, step machines, running and other repetitious movements or forceful rotation with weight on one leg)
Why is Pregnancy a Factor in Piriformis Syndrome?
With the increase of relaxin hormone, which relaxes the joints, the sacroiliac joint also becomes more mobile. The piriformis muscle is attached to the sacrum and so it can be irritated with this extra mobility or shifting of the sacrum.
Also the change in posture due to the weight of baby at the front of the body can cause an anterior pelvic tilt. This can also cause the piriformis muscle to then compress the sciatic nerve.