The Scaroiliac Joint Flashcards
The pelvis consists of two ____ joints and one _____ joint., for a total of three joints.
2 sacroiliac joints
1 pubic symphysis
The sacral surface is composed of _____, whereas the ilial surface is composed of _____.
Sacral surface = hyaline cartilage
Ilial surface = fibrocartilage
What makes the SI joint unique compared to all other joints?
Only 1 muscle crosses the SI joint surface.
_____ is the only muscle that crosses the SI joint surface.
Piriformis
True or False: Joint motion at the SI joint is more influenced by the contractile tissue than arthrokinematics motion.
FALSE
More influenced by arthrokinematics motion
Describe 2 ways in which movement is defined at the SI joint.
- Motion as the ilium moves on the sacrum = ILIOSACRAL motion
- Motion as the sacrum moves on the ilium = SACROILIAC motion
Normal iliosacral motion entails moving the ilium into ___ and into ____.
Anterior rotation
Posterior rotation
The most common SI impairments involve ____ motion.
Iliosacral motion
What are the 2 most common iliosacral impairments?
Anterior (rotation / torsion) and Posterior (rotation / torsion) innominate (which are positional faults)
What is an upslip/downslip?
An abnormal iliosacral motion where one innominate moves either in a cranial or a caudal direction in relation to the other innominate.
How many axes of motion are present at the sacroiliac joint?
6
What is nutation?
Anterior movement of the superior aspect of the sacrum in conjunction with posterior movement of the inferior aspect of the sacrum, or anterior sacral tilt.
What is counternutation?
Posterior movement of the superior aspect of the sacrum in conjunction with anterior movement of the inferior aspect of the sacrum, or posterior sacral tilt.
Sacral nutation is the same motion as bilateral ____, and sacral counternutation is the same motion as bilateral _____.
ilial posterior rotation
ilial anterior rotation
How does movement at the SI joint aid in childbirth? (2)
- When the sacrum moves into counternutation, the rim of the pelvis widens and the outlet narrows. This facilitates movement of the baby toward the outlet.
- When the sacrum moves into nutation, the rim of the pelvis narrows and the outlet widens. This facilitates expulsion and delivery of the baby.
The prevalence of SI joint problems is ~___ %.
25%
List 6 things that may cause SI joint problems.
- Pregnancy / childbirth
- Trauma
- Degenerative joint disease
- S/P lumbar fusion
- Hypermobility
- Positional Faults
____ is the hormone released into the bloodstream that causes ligaments to become more lax.
RELAXIN
______ must be ruled out when assessing SI joint dysfunction.
Ankolysing spondylitis
Characterized by a gradual fusion of the vertebrae, beginning at the lower spinal segments and progressing upward
Describe the position of the ASIS and PSIS in patients with iliosacral impairments with anterior torsion and posterior torsion (2).
- The patient with an anterior torsion should have a lower ASIS and a higher PSIS on the side of the impairment.
- The patient with a posterior torsion should have a lower PSIS and a higher ASIS on the side of the impairment.
The patient with a sacroiliac motion positional fault could have ____ in their sacrum. What 2 structures should be palpated to assess for this positional fault?
ASYMMETRY
Palpate
- Sacral sulci
- Inferior lateral angle
If the patient has a positional fault into sacral nutation, the ____ should be deeper than ‘normal’, whereas if the patient has a positional fault into sacral counternutation, the ______ will be deeper than ‘normal’
Sacral sulci
Inferior lateral angle
Lumbar forward bending can provoke a _____ torsion positional fault, while lumbar backward bending can provoke a ____ torsion positional fault.
Lumbar Forward bending = POSTERIOR torsion
Lumbar Backward bending = ANTERIOR torsion
_____ of the ASIS causes a stretch at to the posterior SIJ ligament, while _____ of the ASIS causes stretch to the anterior SIJ ligament.
Compression = stretch posterior SIJ Distraction = stretch anterior SIJ
Weakness in what 3 muscles can contribute to anterior torsions at the SI joint?
Abdominal muscles
Gluteus maximus
Hamstrings
Weakness in what 4 muscles can contribute to posterior torsions at the SI joint?
Paraspinals
Iliopsoas
Rectus femoris
TFL
In general, tests involving either palpation for position or mobility of the sacroiliac joint are associated with ____ reliability.
POOR
What number of positive special tests is needed to rule in a diagnosis of SI joint involvement? (2)
3 out of 6 special tests must be positive
2 out of 4 special tests must be positive
List the 4 special tests, for which 2 must be positive, to rule in SI joint pathology.
Distraction
Compression
Thigh thrust
Sacral thrust
List the 6 special tests, for which 3 must be positive, to rule in SI joint pathology.
Distraction Compression Thigh thrust Sacral thrust Gaenslen’s Test left side Gaenslens’s Test right side
List 4 interventions used to treat SI joint pathologies.
- Joint manipulations/mobilizations (regardless of whether the joint is hypermobile)
- Trunk strengthening exercises
- Patient education regarding positioning to avoid asymmetric postures
- Sacroiliac belt to provide added stabilization
