The piriformis is the key external hip rotator and the primary landmark of the greater sciatic foramen, dividing it into the suprapiriform (superior gluteal vessels and nerve) and infrapiriform (sciatic nerve, inferior gluteal, pudendal) compartments. Piriformis syndrome is a diagnosis of exclusion, sciatic nerve irritation from piriformis compression or anatomical variants where the sciatic nerve passes through the piriformis rather than below it.
An expanded entry for Piriformis.
| Origin | Anterior sacrum (S2-S4 sacral foramina levels) and greater sciatic notch margin |
|---|---|
| Insertion | Superior surface of the greater trochanter medial to the gluteus medius insertion |
| Nerve Supply | Branches from S1, S2 (variable, sometimes the nerve to piriformis, sometimes direct sacral plexus branches) |
| Blood Supply | Superior and inferior gluteal arteries |
| Actions |
|
|---|
In the anatomical piriformis variant (sciatic nerve piercing the piriformis), the Freiberg sign (passive hip internal rotation in extension) provokes sciatic symptoms by mechanically compressing the nerve. In the normal relationship, the sciatic nerve is adjacent to the piriformis inferior border and can be compressed by piriformis spasm or hypertrophy.
The FAIR test (hip Flexion, Adduction, Internal Rotation) compresses the sciatic nerve between the piriformis and the ischium, reproducing symptoms in piriformis syndrome. Diagnostic injection into the piriformis muscle with ultrasound or CT guidance provides temporary relief and confirms the diagnosis. Botulinum toxin injection into the piriformis reduces spasm for 3-4 months.
Deep gluteal palpation medial to the greater trochanter midpoint reproduces piriformis tenderness. The tendinous insertion is palpable at the superior trochanter with the hip in flexion-external rotation.
Sciatic nerve irritation from piriformis spasm or anatomical variation producing buttock and posterior thigh pain managed with FAIR stretching, injection, and botulinum toxin.
This website uses cookies to enhance your experience. Some are essential for site functionality, while others help us analyze and improve your usage experience. Please review your options and make your choice.
If you are under 16 years old, please ensure that you have received consent from your parent or guardian for any non-essential cookies.
Your privacy is important to us. You can adjust your cookie settings at any time. For more information about how we use data, please read our privacy policy. You may change your preferences at any time by clicking on the settings button below.
Note that if you choose to disable some types of cookies, it may impact your experience of the site and the services we are able to offer.
Some required resources have been blocked, which can affect third-party services and may cause the site to not function properly.
This website uses cookies to enhance your browsing experience and ensure the site functions properly. By continuing to use this site, you acknowledge and accept our use of cookies.
