Dr. Ebraheim’s educational animated video describes the anatomy of the piriformis muscle.
The sciatic nerve may become compressed or irritated by the piriformis muscle. The piriformis muscle is one of the six lateral hip rotators.
•Superior Gemellus muscle
•Obturator internus muscle
•Inferior gemellus muscle
•Obturator externus muscle
•Quadratus femoris muscle
The nerve to piriformis is a nerve that innervates the piriformis muscle (L5,S1,S2). Normally the sciatic nerve passes beneath the piriformis muscle. The piriformis muscle arises from the sacroiliac joint capsule at the anterior surface of the lateral process of the sacrum and gluteal surface of the ilium at the margin of the greater sciatic notch. The piriformis muscle is inserted into the superior border of greater trochanter. Because the piriformis muscle also arises from the capsule of the SI joint, the association of piriformis syndrome and SI joint pain exists. Be aware of possible anatomical variation of the sciatic nerve in relationship to the piriformis muscle.
Anatomical variation of the sciatic nerve: four types of variations. The sciatic nerve is composed of the tibial and peroneal divisions which are usually bound together but sometimes may divide as they pass the piriformis muscle.
Relation of the sciatic nerve to the piriformis muscle:
1-normal relationship with the sciatic nerve passing beneath piriformis muscle.
2- piriformis divided into two parts with the peroneal division of the sciatic nerve passing between the two parts of the pirirfomis muscle.
3- peroneal division of the sciatic nerve passes over the muscle and the tibial division passes beneath the undivided piriformis muscle.
4- the entire nerve passes through the divided piriformis muscle.
Clinical significance of the pirirofmis muscle:
The piriformis fossa is the proximal entry point for most intrameduallry rod placement.
Piriformis syndrome: diagnosis of piriformis syndrome: high index of suspicion, patient history and exam, EMG and bone scan not very helpful.
Symptoms: occasionally develops from blunt trauma to the buttocks. Localized buttock pain increased by sitting or driving. Tenderness in the sciatic nerve. Pain increased by bicycling or running in young individuals. Radicular symptoms with pain and paresthesia, however it is not common. Pain may be present when palpating directly deep into the area of the greater sciatic notch. Pain may be present when palpating directly deep into the area of the greater sciatic notch.
Lasegue’s maneuver: reproduction of the pain by the hip being flexed to 90 degreeas and the knee extended.
The sciatic nerve is compressed by the piriformis muscle, fibrous bands or by vascular anomalies.
Piriformis syndrome: diagnosis: MRI: enlarged piriformis, anomalies of the vessels, compression of the nerve. Diagnostic injection is helpful.
•Surgical release of the piriformis muscle and decompression of the sciatic nerve is the last resort.
Become a friend on facebook:
Follow me on twitter:
Please rate video.
Average 0.0 of 0 Ratings