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PIRIFORMIS
SYNDROME
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MUSCLE 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.
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Piriformis
Syndrome
Features
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A chronic nagging ache, pain, tingling, or numbness
starts in the buttocks
can extend along the course of the sciatic nerve
down the entire back of the thigh and calf, and sometimes into the foot
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).
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The piriformis syndrome is a rare entrapment
neuropathy in which the sciatic nerve is
compromised by an abnormal piriformis muscle.
Approximately 6% of lower back pain and
sciatica cases seen in a general practice may be
caused by piriformis syndrome
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Signs
and symptoms of pain in the sciatic nerve
distribution:
Gluteal area
Posterior thigh
Posterior leg
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
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sciatic notch
Pain exacerbated by lifting the leg and relieved by traction on
the affected extremity
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Causes of Piriformis syndrome
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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
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piriformis syndrome.
Unenhanced axial T1weighted 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
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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
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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
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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
sciatic notch, and piriformis muscle
 Tenderness over piriformis muscle
 Palpable mass in ipsilateral buttock
 Traction of affected limb provides moderate relief of
pain
 Asymmetrical weakness in affected limb
 Lasègue sign positive
Localized pain when pressure is applied over the
piriformis muscle and its tendon, especially when the
hip is flexed at an angle of 90 degrees and the knee
is extended
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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
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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.
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