Piriformis Syndrome - Lecture

Question 1

Origin and insertion of piriformis

Answer 1

O = S2-S4 anterolateral borders

I = medial side of upper greater trochanter

Question 2

Actions of piriformis

Answer 2

ER of hip (major)

ABD when flexed (minor)

Question 3

Nerve/vessels SUPERIOR to piriformis

Answer 3

Superior gluteal n/a/v

Question 4

Nerves/vessels INFERIOR to piriformis

Answer 4

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

Question 5

How does the sciatic n relate to piriformis?

Answer 5

Variable - may be over, under, or in the middle

Question 6

Physio of muscle spasm

Answer 6

Position/cause of strain –> rapid lengthening –> reflex contraction –> PAIN-SPASM CYCLE (gamma and alpha fibers of reflex arc activate each other)

Question 7

Secondary/tertiary fibers in the brain for pain sensation

Answer 7

A-delta fibers = to thalamus and sensory cortex (localization/discrimination)

C fibers = other places (behavior modification, memory, etc.)

Question 8

Things that lower pain threshold, increasing likelihood of developing spasm

Answer 8

Sympathetics (NE)

Vasoconstriction

Question 9

What is facilitation? What causes this in the tissue?

Answer 9

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

Question 10

How does facilitation affect the sciatic nerve?

How can you tell that these are what the problem is?

Answer 10

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

Question 11

This nociception theory behind piriformis syndrome disrupts the balance between ____ and ____

Answer 11

Habituation (lessened response)

Sensitization (heightened response)

Question 12

2 categories of pathologies that can cause piriformis syndrome

Answer 12

Functional

Structural

Question 13

Functional causes of piriformis syndrome

Answer 13

• Planted foot + forcible rotation of trunk
• Sitting in awkward position for long time
• Sacral unleveling (short leg)
• Pelvic instability (SI joint)

Question 14

Structural causes of piriformis syndrome

Answer 14

• Fibrosis/scarring
• Hematoma
• Mass
• Anatomic relationship btwn piriformis and sciatic n. (piercing or not)

Question 15

Presentation of piriformis syndrome

Answer 15

• 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

Question 16

PE/Work-Up for piriformis syndrome

Answer 16

• Visualize/observe transverse plane of motion (easy ER, bad IR)
• Palpation (CS, IT band, trigger points)
• Neuro testing
• Special tests
• Radiology/Diagnostics
• Osteopathic exam

Question 17

**Trigger point vs. tender point

Answer 17

Trigger - painful radiation along nerve distribution

Tender - local tenderness

Question 18

4 special tests for piriformis (explain each)

Answer 18

• 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

Question 19

DDx for piriformis syndrome

Answer 19

SD
Herniated disc
Foraminal stenosis
Intraspinal lesion
Pelvic mass
Hamstring injury
SI disease (AS, etc.)
Facet syndrome
Diabetic neuropathy

Question 20

Tx for piriformis syndrome (in office)

Answer 20

MFR, ME, CS
NSAIDs
Injections (steroids)
Surgery

Question 21

Tx for piriformis syndrome (self)

Answer 21

Stretching - pigeon posture, figure 4 position, IR, sway

Warm baths