Pelvic Girdle & Sacroiliac Joint Flashcards
Describe the anatomy of the sacroiliac joint
- largest axial joint in the body
- connects spine to pelvis
- allows for transfer of load from lumbar spine to lower extremities
- held together with several ligaments and fibrous capsule
- surrounded by muscular support
Do any muscles act directly on the sacroiliac joint
No
How are movements of the sacroiliac joint produced
By muscles acting on the trunk and lower limbs
What type of loads do the sacroiliac joint transfers?
Large bending moments and compression loads
What type of load does the sacroiliac joint does not have much stability against
Shear loads
How is shear load resisted
Transverse abdominus and pelvic floor muscles (elevator ani) help apply compression load to resist shear
What type of force opposes shear force
Compression force
How much flexion/extension is there in sacroiliac joint ROM
~ 3 degrees
How much axial rotation in Sacroiliac joint ROM
~ 1.5 degrees
How much lateral bending at the sacroiliac joint?
~0.8 degrees
What is nutation
Sacral flexion
- associated with spinal extension
What is counternutation
Sacral extension
- associated with spinal flexion
What direction does the superior sacrum tilt in nutation
Anteriorly
What direction does the coccyx tilt in nutation
Posteriorly
What structure restricts sacral nutation
Sacrotuberous ligament
What muscle helps restrict nutation and where is its attachment
Biceps femoris, ichial tuberosity
In what sacral position is load transfer more effective
When the sacrum is notated or tilted forward at its superior aspect
Which direction does the coccyx rotate in counter nutation (from mutated state back to neutral state)
Rotates anteriorly
What direction does the superior sacrum move in sacral counter nutation
Posterior tilt
What structure restricts sacral counter nutation
Long dorsal sacroiliac ligament
Can also be achieved by latissimus dorsi though its attachment at the thoracolumbar fascia
What plane does anterior and posterior rotation of the innominate (pelvis) occur
Sagittal plane
Should anterior rotation occur during weight bearing
No.
During single leg stance, which direction does innominate (pelvic) rotation occur and why
Posteriorly to put sacrum in mutated position - creates close pack position and maximum amount of stability in the joint
In what plane does inflate and outflare occur?
Transverse plane
What kind of motion/tasks do inflare and outflare occur
During rotation and lateral bending tasks
What is the gold standard diagnosis for SI joint pain
Fluoroscopically guided diagnostic steroid injection
What is the primary mechanism of SI joint injury
Combination of axial loading and abrupt rotation
What type of surgery can also increase angular more and stresses across the SI joint
Lumbar fusion
Wha are the 4 European Guidelines on the Diagnosis and Treatment of Pelvic Girdle Pain
- groin pain
- pain below L5
- Pain at the region of the PSiS
- Absence of midline lumbar pain
What are the SI joint provocation test clusters
- FABER
- Distraction
- Compression
- Thigh thrust
- Sacral thrust
- Gaenslan’s test
3 positive rests required for diagnosis of SI joint pain
What is the FABER test ?
What type of stress is applied to the SI joint?
Flexion, abduction, ER
- applies tensile force on anterior aspect of SI joint
- positive test = report suction of pain
What is the distraction test?
What type of stress is applied to the SI joint?
- lateral force to bilateral ASIS
- applies tensile force on anterior aspect of SI joints
- positive test - reproduction of pain
What is Compression test
What type of stress is applied to the SI joint?
- patient sidelying, with application of downward compression on ilium
- applies compression force across SI joint
= pain = positive test
What is the thigh thrust?
What type of stress is applied to the SI joint?
- patient supine, with affected side flexed to 90 degrees and examiner applies axial pressure through the femur
- applied anteroposterior shear stress on the SI join
What is the sacral thrust test?
What type of stress is applied to the SI joint?
- patient laying prone, examiner applies anteriorly directed force on the sacrum
- applies anterior shear forces to both SI joints
What is Gaenslan’s test?
What type of stress is applied to the SI joint?
- symptomatic leg placed in extension off the table, opposite leg held in flexion
- applies torsional stress on the SI join
- modified version performed in side lying
Is sacral fusion recommended for SI joint pain
No - there is no evidence for sacral fusion surgery
Structural/true leg length discrepancy definition
Results from inequalities in boney structure
Functional LLD deficiency
Caused by altered mechanics of the lower extremity
What rotation occurs off the innominate (pelvis) and in what plane during functional LLD
Anterior rotation, sagittal plane
What other downstream effects we can see in function LLD?
Ie how are the femur, the knee, the tibia and the foot affected
- weakness of structural mal alignment of pelvis in frontal plane
- functional lengthening of the lower limb
- femoral internal rotation
- valgus knee aka medial knee excursion
- tibial internal rotation
- foot pronation
What is the gold standard for measuring LLD
Radiographs
What re the 2 different clinical measurements of LLD
- with tape measure
= with a block
How to measure structural LLD with a tape measure
- ## ASIS to medial malleolus
How to measure functional/apparent LLD with a tape measure
Umbilicus go medial malleolus
Which clinical measurement of LLD indirect and which is direct
- indirect - blocks
- direct - tape measure
Which LLD is measured first
- structural done prior to the functional
- ie ASOS to med mal done prior to umbilicus to med mal
What is the recommended treatment for Functional LLD?
-physical therapy to address underlying issue
Treatment options for true LLD?
- conservative (less than 2cm)
- Surgical
What are they surgical treatments for LLD
- epiphesiodesis
- lower limb shortening’
- Mac 3inches in femur, max 2 inches in tibia
- external limb lengthening
- internal limb lengthening
