Piriformis Syndrome - Lecture Flashcards
Origin and insertion of piriformis
O = S2-S4 anterolateral borders
I = medial side of upper greater trochanter
Actions of piriformis
ER of hip (major)
ABD when flexed (minor)
Nerve/vessels SUPERIOR to piriformis
Superior gluteal n/a/v
Nerves/vessels INFERIOR to piriformis
Inferior gluteal n/a/v
Pudendal n
Internal pudendal a/v
Post. femoral cutaneous n.
Nerves to obturator internus, superior/inferior gemelli, and quadratus femoris
How does the sciatic n relate to piriformis?
Variable - may be over, under, or in the middle
Physio of muscle spasm
Position/cause of strain –> rapid lengthening –> reflex contraction –> PAIN-SPASM CYCLE (gamma and alpha fibers of reflex arc activate each other)
Secondary/tertiary fibers in the brain for pain sensation
A-delta fibers = to thalamus and sensory cortex (localization/discrimination)
C fibers = other places (behavior modification, memory, etc.)
Things that lower pain threshold, increasing likelihood of developing spasm
Sympathetics (NE)
Vasoconstriction
What is facilitation? What causes this in the tissue?
Changes in CNS and tissues that lead to LESS stimulus needed for SAME pain response
Release of PGs, bradykinin, histamine, other chemicals that cause lowered nociceptor threshold –> increased input to the CNS
How does facilitation affect the sciatic nerve?
How can you tell that these are what the problem is?
The inflammatory agents irritate the NERVI NEURVORUM that supply the sciatic nerve, causing pain in the sciatic nerve distribution
DTRs, strengths, etc. from the sciatic nerve are still in tact
This nociception theory behind piriformis syndrome disrupts the balance between ____ and ____
Habituation (lessened response)
Sensitization (heightened response)
2 categories of pathologies that can cause piriformis syndrome
Functional
Structural
Functional causes of piriformis syndrome
- Planted foot + forcible rotation of trunk
- Sitting in awkward position for long time
- Sacral unleveling (short leg)
- Pelvic instability (SI joint)
Structural causes of piriformis syndrome
- Fibrosis/scarring
- Hematoma
- Mass
- Anatomic relationship btwn piriformis and sciatic n. (piercing or not)
Presentation of piriformis syndrome
- Low back or butt pain that may radiate down leg
- Tenderness over lateral butt/hip
- Paresthesias along sciatic nerve distribution
- Aggravation by prolonged sitting
- NO DTR or MOTOR DEFICITS
PE/Work-Up for piriformis syndrome
- Visualize/observe transverse plane of motion (easy ER, bad IR)
- Palpation (CS, IT band, trigger points)
- Neuro testing
- Special tests
- Radiology/Diagnostics
- Osteopathic exam
**Trigger point vs. tender point
Trigger - painful radiation along nerve distribution
Tender - local tenderness
4 special tests for piriformis (explain each)
- Lasegue - SLR
- Well Leg Raise - contralateral SLR
- Pace sign - pain/weak abd/ER of hip w/ resistance
- Freiberg sign - pain w/ passive IR of extended thigh
DDx for piriformis syndrome
SD Herniated disc Foraminal stenosis Intraspinal lesion Pelvic mass Hamstring injury SI disease (AS, etc.) Facet syndrome Diabetic neuropathy
Tx for piriformis syndrome (in office)
MFR, ME, CS
NSAIDs
Injections (steroids)
Surgery
Tx for piriformis syndrome (self)
Stretching - pigeon posture, figure 4 position, IR, sway
Warm baths
