The piriformis syndrome is a
condition in which the piriformis muscle irritates the sciatic nerve,
causing pain in the buttocks and referring pain along the course of the
sciatic nerve. This referred pain, called "sciatica", often goes down the
back of the thigh and/or into the lower back. Patients generally complain
of pain deep in the buttocks, which is made worse by sitting, climbing
stairs, or performing squats. The piriformis muscle assists in abducting
and laterally rotating the thigh. In other words, while balancing on the
left foot, move the right leg directly sideways away from the body and
rotate the right leg so that the toes point towards the ceiling. This is
the action of the right piriformis muscle.
The sciatic nerve usually passes underneath
the piriformis muscle, but in approximately 15% of the population, it
travels through the muscle. It is thought that acute or chronic injury
causes swelling of the muscle and irritates the sciatic nerve, resulting
in sciatica. Patients with an aberrant course of the nerve through the
muscle are particularly predisposed to this condition.
The piriformis syndrome is diagnosed primarily
on the basis of symptoms and on the physical exam. There are no tests that
accurately confirm the diagnosis, but X-rays, MRI, and nerve conduction
tests may be necessary to exclude other diseases. Some of the other causes
of sciatica include disease in the lumbar spine (e.g. disc herniation),
chronic hamstring tendonitis, and fibrous adhesions of other muscles
around the sciatic nerve.
Once properly diagnosed, treatment is
undertaken in a stepwise approach. Initially, progressive piriformis
stretching is employed, starting with 5 seconds of sustained stretch and
gradually working up to 60 seconds. This is repeated several times
throughout the day. It is important that any abnormal biomechanical
problems, such as overpronation of the foot or other coexisting
conditions, are treated. This stretching can be combined with physical
therapy modalities such as ultrasound. If these fail, then injections of a
corticosteroid into the piriformis muscle may be tried. Finally, surgical
exploration may be undertaken as a last resort.
Stretching the muscle often duplicates the pain. To do the piriformis
stretch, lie on your back, and flex the right hip and knee. Now, while
grasping the right knee with your left hand, pull the knee towards your
left shoulder. This adducts and flexes the hip. In this position, grasp
just above the right ankle with the right hand, and rotate the ankle
outwards. This applies internal rotation to the hip and completes the
stretch. Another way to do this stretch is to stand on your left foot and
place the right foot on a chair, such that the right knee and hip are
flexed at about 90 degrees. Now, using the right hand, press the right
knee across towards the left side of the body while keeping the ball of
the right foot on the same spot on the chair.
Alternate Exercise 2.
Place the right knee on the
ground roughly in line with your left shoulder. The right foot should be
just in front of the left knee. Press your hips towards the ground so that
your bodyweight is on your right leg. As you move down the right knee
comes closer to the left shoulder. You should feel a gentle pull deep in
the right hip / buttocks.