Piriformis Muscle anatomy | unique special test

                             Piriformis Muscle anatomy

The piriformis muscle (R. L) is one of the lateral rotators of the hip that also facilitates hip abduction and extension.
Origin:
Front of the sacrum between S01, S02, S03, and S04 anterior sacral foramina 

Insertion:
Upper border of the greater trochanter 

Innervation:
Spinal nerves (L05-S02)

 Action:
 abduction, External rotation, extension of the hip joint; aids in stabilization of the hip

Blood supply: Superior and inferior gluteal arteries

Piriformis syndrome may occur from a shortened muscle, causing compression and irritation of the nerve at this site. The nerve is protected under the gluteus maximus as it courses between the ischial tuberosity and greater trochanter, although injury may occur in this region with hip dislocation or reduction.
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Piriformis syndrome. A recent case report identified weakness of the hip extensors and abductors resulting in hip adduction and internal rotation (valgus collapse) during functional activities as the apparent causes of overuse of the piriformis muscle and compression of the sciatic nerve.
Strengthening and functional retraining of the gluteus maximus and gluteus medius along with correction of the faulty movement patterns resulted in alleviation of symptoms and functional improvement,




Piriformis Test.
15% of the population buttock and sciatica may be experienced , the sciatic nerve, all or in part, passes through the piriformis muscle rather than below it

These people are more likely to suffer from this relatively rare condition, piriformis syndrome.

patient position--
 side lying position with the test leg upper most.  
patient flexes the affected side hip to 60° with the knee flexed.

 Examiner position----
 affected side of leg  and  stabilizes the hip with one hand and  downward pressure applies to the knee .
 pain start during test positive sign of piriformis muscle is tight,
 pain results in the buttock and sciatica may be experienced by the patient due to piriformis muscle is  pinching the sciatic nerve,
 Resisted lateral rotation with the muscle on stretch (hip medially rotated) can cause the same sciatica.

Deep palpation of piriformis tenderness --
through elbow wrist and thumb