|Classification according to ICD-10|
|G57.8||Other lower extremity mononeuropathies|
|ICD-10 online (WHO version 2019)|
The piriformis syndrome is a compression of the sciatic nerve (sciatic nerve) as it passes through the infrapiriform foramen between the pelvic bone and the piriformis muscle .
Piriformis syndrome usually occurs after trauma and is associated with severe pain in the buttock region . However, it has not yet been established that these symptoms are actually caused by compression of parts of the sciatic nerve.
The piriformis syndrome is often confused with a disc problem, since the symptoms that appear in piriformis syndrome resemble a root irritation of the sciatic nerve.
Piriformis syndrome often occurs when no clear cause of "sciatic pain" can be diagnosed. The sciatic nerve leaves the pelvis at the level of the buttocks, runs to the back of the thigh and finally sends its branches to the tips of the feet. At the exit point, the nerve pulls together and directly below the piriformis muscle through a bony opening in the pelvis. The actual cause is the inadequate lengthening capacity (either through tensioning or shortening) of the muscle, because the piriformis muscle tends to do this over time. The muscle mass remains the same, the muscle becomes thicker. This increased need for space is at the expense of the sciatic nerve. There is irritation. The cause of this behavior has not yet been precisely clarified scientifically.
Possible causes are:
- long one-sided sitting (computer work, driving a car)
- Money pocket in the back pocket
- Overexertion (especially bent over posture)
- Lifting heavy objects out of the straddle
Muscle tests are one way to differentiate piriformis syndrome from other causes. The piriformis muscle acts as an external rotator when the hip is extended and as an abductor when the hip is flexed. If these two movements, carried out against resistance, lead to a pain provocation, this indicates a piriformis syndrome.
The external rotation test can be performed in the supine position with the lower legs hanging over the edge. The examiner now holds his hands against the two inner ankles and asks the patient to press their feet inward against this resistance. This results in external rotation and tension in the external rotators of the hips, which are painful in the case of piriformis syndrome.
The abduction is tested while sitting. The examiner holds his hands on the outside of his knees and the patient pushes his knees outward against this resistance.
A stretch test can also provoke the pain. The stretching can be done as a passive adduction of the leg while sitting or as a passive internal rotation of the thigh by moving the lower leg hanging down over the edge in the supine position outwards (Freiberg symbol).
Massage , trigger point treatment and movement therapy ( stretching exercises ) are used for treatment .
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