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MUSCLE FACTSMUSCLE FACTS An external rotator, weak

abductor, and weak flexor of the hip

Provides postural stability during ambulation and standing

Originates at the anterior surface of the sacrum, usually at the levels of vertebrae S2 through S4, at or near the sacroiliac joint capsule.

Attaches to the superior medial aspect of the greater trochanter via a round tendon

In many individuals, the tendon merges with the tendons of the obturator internus and gemelli muscles

The piriformis muscle is innervated by spinal nerves S1 and S2—and occasionally also by L5.

PIRIFORMIS PIRIFORMIS SYNDROMESYNDROME

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Piriformis Syndrome Features

1.1. A chronic nagging ache, pain, tingling, or numbness A chronic nagging ache, pain, tingling, or numbness 2.2. starts in the buttocks starts in the buttocks 3.3. can extend along the course of the sciatic nervecan extend along the course of the sciatic nerve4.4. down the entire back of the thigh and calf, and sometimes into the foot down the entire back of the thigh and calf, and sometimes into the foot 5.5. Pain worsens when the piriformis is pressed against the sciatic nerve-Pain worsens when the piriformis is pressed against the sciatic nerve-

(eg, while sitting on a toilet, a car seat, or a narrow bicycle seat or while running). (eg, while sitting on a toilet, a car seat, or a narrow bicycle seat or while running).

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The piriformis syndrome is a rare entrapmentneuropathy in which the sciatic nerve iscompromised by an abnormal piriformis muscle.

Approximately 6% of lower back pain andsciatica cases seen in a general practice may becaused by piriformis syndrome

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Signs and symptoms of pain in the sciatic nerve Signs and symptoms of pain in the sciatic nerve distribution: distribution: Gluteal areaGluteal areaPosterior thighPosterior thighPosterior legPosterior legLateral aspect of the foot.Lateral aspect of the foot.

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Demography and features of Piriformis Syndrome

Female-to-Male incidence ratio of piriformis syndrome is 6:1 Positive Lasegue sign-straight leg raising test Sausage-shaped mass over the piriformis muscle Gluteal atrophy in chronic cases Trauma to the region Pain in the sacroiliac region, gluteal muscles, or greater

sciatic notch Pain exacerbated by lifting the leg and relieved by traction on

the affected extremity

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Causes of Piriformis syndrome

Trauma to the buttocks or gluteal region is the most common cause of piriformis syndrome.

Skiers, truck drivers, tennis players, and long-distance bikers are at high risk.

In Morton foot, the prominent head of the second metatarsal causes foot instability and a reactive contraction of the external rotators of the hip during gait.

Spinal Stenosis can lead to bilateral piriformis tenderness. Anatomic variations of the divisions of the sciatic nerve

above, below, and through the belly of the piriformis muscle may be causative factors.

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40-year-old man with piriformis syndrome. Unenhanced axial T1-weighted MR image of sacrum- shows accessory fibers of right piriformis muscle (a) overlying right S2 nerve (arrow) and attaching medially.

Note that accessory fibers of right piriformis muscle and right S2 nerve are of normal signal intensity.

p = normal left piriformis muscle at sacral attachment.

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40-year-old man with piriformis syndrome.

Unenhanced oblique coronal T1-weighted MR image shows accessory fibers of right piriformis muscle (a) anterior to and obscuring right S2 nerve.

p = normal right and left piriformis muscles.

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Symptoms Pain with sitting, standing, or

lying longer than 15 to 20 minutes

Pain and/or paresthesia radiating from sacrum through gluteal area and down posterior aspect of thigh, usually stopping above knee

Pain improves with ambulation and worsens with no movement

Pain when rising from seated or squatting position

Change of position does not relieve pain completely

Contralateral sacroiliac pain

Difficulty walking (eg, antalgic gait, foot drop)

Numbness in foot Weakness in ipsilateral

lower extremity Headache Neck pain Abdominal, pelvic, and

inguinal pain Dyspareunia in women Pain with bowel

movements

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Signs

Tenderness in region of sacroiliac joint, greater Tenderness in region of sacroiliac joint, greater sciatic notch, and piriformis musclesciatic notch, and piriformis muscle

Tenderness over piriformis muscleTenderness over piriformis musclePalpable mass in ipsilateral buttockPalpable mass in ipsilateral buttockTraction of affected limb provides moderate relief of Traction of affected limb provides moderate relief of

painpainAsymmetrical weakness in affected limbAsymmetrical weakness in affected limb Lasègue sign positiveLasègue sign positive

Localized pain when pressure is applied over the Localized pain when pressure is applied over the piriformis muscle and its tendon, especially when the piriformis muscle and its tendon, especially when the hip is flexed at an angle of 90 degrees and the knee is hip is flexed at an angle of 90 degrees and the knee is extendedextended

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Tests for Piriformis Syndrome

The involved hip is flexed, passively adducted, and internally rotated in a standing position.

The involved hip is flexed, passively adducted, and internally rotated while the patient is reclined

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The involved hip is flexed, passively adducted, and internally rotated while the patient is reclined.

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Freiberg test: Forceful internal rotation of the affected side elicits pain.

Beatty maneuver: Patient lies on the uninvolved side and abducts the involved thigh upward, which elicits pain.

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Piriformis Stretch 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 (torso) down the right knee

comes closer to the left shoulder. You should feel a gentle pull deep in the

right hip / buttocks.