Chapter 27

Chapter 27Chapter 27

The Sacroiliac JointThe Sacroiliac Joint

OverviewOverview

The sacroiliac joint (SIJ), which The sacroiliac joint (SIJ), which serves as the point of intersection serves as the point of intersection between the spinal and the lower between the spinal and the lower extremity joints is the least extremity joints is the least understood and, therefore, one of understood and, therefore, one of the most controversial and the most controversial and interesting areas of the spineinteresting areas of the spine

AnatomyAnatomy

The ilium, ischium, and pubic The ilium, ischium, and pubic bone fuse at the acetabulum to bone fuse at the acetabulum to form each innominateform each innominate

Each of the two innominates Each of the two innominates articulate with the sacrum, articulate with the sacrum, forming the sacroiliac joint, and forming the sacroiliac joint, and with each other at the symphysis with each other at the symphysis pubis pubis

AnatomyAnatomy

The sacrum is a strong and The sacrum is a strong and triangular bone located between triangular bone located between the two innominatesthe two innominates

Provides stability to this area and Provides stability to this area and transmits the weight of the body transmits the weight of the body from the mobile vertebral column from the mobile vertebral column to the pelvic region to the pelvic region

AnatomyAnatomy

The articulating surfaces of the sacroiliac The articulating surfaces of the sacroiliac joint differjoint differ– The iliac joint surfaces are formed from The iliac joint surfaces are formed from

fibrocartilagefibrocartilage– The sacral surfaces are formed from hyaline The sacral surfaces are formed from hyaline

cartilage. cartilage. – The hyaline cartilage is 3-5 times thicker than The hyaline cartilage is 3-5 times thicker than

the fibrocartilage, so that between the sacral the fibrocartilage, so that between the sacral and iliac auricular surfaces, the sacroiliac joint and iliac auricular surfaces, the sacroiliac joint is deemed a synovial articulation, or is deemed a synovial articulation, or diarthrosis diarthrosis

AnatomyAnatomy

The configuration of the sacroiliac The configuration of the sacroiliac joints is extremely variable from joints is extremely variable from person to person, and between person to person, and between genders in terms of morphology genders in terms of morphology and mobilityand mobility

These differences are not These differences are not pathological, but are normal pathological, but are normal adaptations adaptations

AnatomyAnatomy

Like other synovial joints, the Like other synovial joints, the sacroiliac joint is reinforced by sacroiliac joint is reinforced by ligaments, but the ligaments of ligaments, but the ligaments of the sacroiliac joint are some of the sacroiliac joint are some of the strongest and toughest the strongest and toughest ligaments of the body ligaments of the body

AnatomyAnatomy

The anterior sacral ligament (ASL) is The anterior sacral ligament (ASL) is an anterior-inferior thickening of the an anterior-inferior thickening of the fibrous capsulefibrous capsule

Relatively weak and thin compared to Relatively weak and thin compared to the rest of the sacroiliac ligamentsthe rest of the sacroiliac ligaments

Extends between the anterior and Extends between the anterior and inferior borders of the iliac auricular inferior borders of the iliac auricular surface, and the anterior border of the surface, and the anterior border of the sacral auricular surface sacral auricular surface

AnatomyAnatomy

The interosseous ligament is a short The interosseous ligament is a short ligament located deep to the dorsal ligament located deep to the dorsal sacroiliac ligamentsacroiliac ligament

Forms the major connection between Forms the major connection between the sacrum and the innominate, the sacrum and the innominate, filling the irregular space posterior-filling the irregular space posterior-superior to the joint between the superior to the joint between the lateral sacral crest, and the iliac lateral sacral crest, and the iliac tuberosity tuberosity

AnatomyAnatomy

The dorsal sacroiliac ligament (long The dorsal sacroiliac ligament (long ligament) connects the PSIS (and a ligament) connects the PSIS (and a small part of the iliac crest) with the small part of the iliac crest) with the lateral crest of the third and fourth lateral crest of the third and fourth segment of the sacrumsegment of the sacrum

This is a very tough and strong ligament This is a very tough and strong ligament Sacral nutation (anterior motion) of the Sacral nutation (anterior motion) of the

sacrum appears to slacken this sacrum appears to slacken this ligament whereas counternutation ligament whereas counternutation (posterior motion) tautens the ligament(posterior motion) tautens the ligament

AnatomyAnatomy

The sacrotuberous ligament is comprised The sacrotuberous ligament is comprised of three large fibrous bands, broadly of three large fibrous bands, broadly attached by its base to the posterior attached by its base to the posterior inferior iliac spine, the lateral sacrum, inferior iliac spine, the lateral sacrum, and partly blended with the dorsal and partly blended with the dorsal sacroiliac ligamentsacroiliac ligament

Stabilizes against nutation (forward Stabilizes against nutation (forward rotation) of the sacrumrotation) of the sacrum

Counteracts against the dorsal and Counteracts against the dorsal and cranial migration of the sacral apex cranial migration of the sacral apex during weight bearing during weight bearing

AnatomyAnatomy

The sacrotuberous ligament The sacrotuberous ligament extends from the ischial spine to extends from the ischial spine to the lateral margins of the sacrum the lateral margins of the sacrum and coccyx, and laterally to the and coccyx, and laterally to the spine of the ischium spine of the ischium

Counteracts against nutation of Counteracts against nutation of the sacrumthe sacrum

AnatomyAnatomy

The pubic symphysis is classified The pubic symphysis is classified as a symphysis as it has no as a symphysis as it has no synovial tissue or fluid, and synovial tissue or fluid, and contains a fibrocartilaginous disc contains a fibrocartilaginous disc

The bone surfaces of this joint are The bone surfaces of this joint are covered with hyaline cartilage, covered with hyaline cartilage, but are kept apart by the but are kept apart by the presence of the disc presence of the disc

AnatomyAnatomy

Thirty-five muscles attach directly Thirty-five muscles attach directly to the sacrum and/or innominateto the sacrum and/or innominate

These muscles primarily function These muscles primarily function to stabilize the sacroiliac joint to stabilize the sacroiliac joint rather than to move itrather than to move it

AnatomyAnatomy

The piriformis muscleThe piriformis muscle Primarily functions to produces Primarily functions to produces

external rotation and abduction of the external rotation and abduction of the femurfemur

Also thought to function as an internal Also thought to function as an internal rotator and abductor of the hip if the rotator and abductor of the hip if the hip joint is flexed beyond 90°hip joint is flexed beyond 90°

Capable of restricting sacroiliac joint Capable of restricting sacroiliac joint motion motion

AnatomyAnatomy

The term “pelvic floor muscles” primarily The term “pelvic floor muscles” primarily refers to the levator ani, a muscle group refers to the levator ani, a muscle group composed of the pubococcygeus, composed of the pubococcygeus, puborectalis and iliococcygeuspuborectalis and iliococcygeus

The levator ani muscles join the coccygeus The levator ani muscles join the coccygeus muscles to complete the pelvic floormuscles to complete the pelvic floor

The pelvic floor muscles work in a The pelvic floor muscles work in a coordinated manner to increase intra-coordinated manner to increase intra-abdominal pressure, provide rectal support abdominal pressure, provide rectal support during defecation, inhibit bladder activity, during defecation, inhibit bladder activity, help to support the pelvic organs, and assist help to support the pelvic organs, and assist in lumbopelvic stability in lumbopelvic stability

AnatomyAnatomy

NeurologyNeurology– It remains unclear precisely how the It remains unclear precisely how the

anterior and posterior aspects of the anterior and posterior aspects of the sacroiliac joint are innervated, although sacroiliac joint are innervated, although the anterior portion of the joint likely the anterior portion of the joint likely receives innervation from the posterior receives innervation from the posterior rami of the L2‑S2 rootsrami of the L2‑S2 roots

– Contribution from these root levels is Contribution from these root levels is highly variable and may differ among the highly variable and may differ among the joints of given individuals joints of given individuals

– It is the joint’s highly variable and complex It is the joint’s highly variable and complex innervation that produces a very diffuse innervation that produces a very diffuse pattern of pain referral from this area pattern of pain referral from this area

BiomechanicsBiomechanics

The pelvic area must function to absorb The pelvic area must function to absorb the majority of the lower extremity the majority of the lower extremity rotation, while still permitting motion to rotation, while still permitting motion to occuroccur

It is likely, that the movement of the It is likely, that the movement of the pelvis is in the nature of deformations and pelvis is in the nature of deformations and slight gliding motions around a number of slight gliding motions around a number of undefined axes, with the joints of the undefined axes, with the joints of the pelvic ring deforming in response to body pelvic ring deforming in response to body weight and ground reaction forcesweight and ground reaction forces


There is very little agreement, There is very little agreement, either among disciplines, or even either among disciplines, or even within disciplines about the within disciplines about the biomechanics of the pelvic biomechanics of the pelvic complex. The results from the complex. The results from the numerous studies on mobility of the numerous studies on mobility of the sacroiliac joint have led to a variety sacroiliac joint have led to a variety of different hypotheses and models of different hypotheses and models of pelvic mechanics over the yearsof pelvic mechanics over the years


Osteopathic modelOsteopathic model– The sacrum rotates around two The sacrum rotates around two

oblique axesoblique axes– The innominates are capable of The innominates are capable of

rotating anteriorly and posteriorlyrotating anteriorly and posteriorly– Distinction made between sacroiliac Distinction made between sacroiliac

impairment and iliosacral impairment and iliosacral impairment impairment


Chiropractic modelChiropractic model– As one innominate flexes, the As one innominate flexes, the

ipsilateral sacral base moves ipsilateral sacral base moves anterior and inferior, and as the anterior and inferior, and as the other innominate extends, the sacral other innominate extends, the sacral base on that side moves posterior base on that side moves posterior and superiorand superior


Biomechanical modelBiomechanical model– When the sacrum nutates, or flexes, When the sacrum nutates, or flexes,

relative to the innominate, a linear relative to the innominate, a linear glide occurs between the two L-glide occurs between the two L-shaped articular surfaces of the shaped articular surfaces of the sacroiliac joint.sacroiliac joint. The shorter of the two lengths, level with The shorter of the two lengths, level with

S 1, lies in a vertical planeS 1, lies in a vertical plane The longer length, spanning S 2-4, lies in The longer length, spanning S 2-4, lies in

an anterior-posterior plane an anterior-posterior plane


Snijders and Vleeming defined kinetics Snijders and Vleeming defined kinetics within the lumbar/pelvic/hip region by within the lumbar/pelvic/hip region by introducing the concepts of ‘extrinsic’ introducing the concepts of ‘extrinsic’ and ‘intrinsic’ stability of the pelvic and ‘intrinsic’ stability of the pelvic girdle and the ‘self-locking’ mechanismgirdle and the ‘self-locking’ mechanism

Their work instituted the terms Their work instituted the terms form form closureclosure and and force closureforce closure to describe the to describe the passive and active forces that help to passive and active forces that help to stabilize the pelvis and the sacroiliac stabilize the pelvis and the sacroiliac jointjoint


Form closureForm closure– Form closure refers to a state of stability Form closure refers to a state of stability

within the pelvic mechanism, with the within the pelvic mechanism, with the degree of stability dependent upon its degree of stability dependent upon its anatomy, with no need for extra forces to anatomy, with no need for extra forces to maintain the stable state of the system maintain the stable state of the system

– Relies on incongruity of the articular Relies on incongruity of the articular surfaces, the friction coefficient of the surfaces, the friction coefficient of the articular cartilage and the shape of the articular cartilage and the shape of the articulating surfacesarticulating surfaces


Force closureForce closure– Force closure requires intrinsic and extrinsic Force closure requires intrinsic and extrinsic

forces to keep the sacroiliac joint stableforces to keep the sacroiliac joint stable– These dynamic forces involve the These dynamic forces involve the

neurological and myofascial systems, and neurological and myofascial systems, and gravity. Together, these components gravity. Together, these components produce a self-locking mechanism for the produce a self-locking mechanism for the sacroiliac joint sacroiliac joint

– Critical to the self-locking mechanism is the Critical to the self-locking mechanism is the ability of the sacrum to nutateability of the sacrum to nutate

ExaminationExamination

Under the premise that a relationship Under the premise that a relationship between pelvic asymmetry and low between pelvic asymmetry and low back pain exists, orthopedic, back pain exists, orthopedic, osteopathic, and physical therapy texts osteopathic, and physical therapy texts promote the use of pain provocation promote the use of pain provocation (symptom-based) tests and (symptom-based) tests and biomechanical (mechanical-based) tests biomechanical (mechanical-based) tests that include static (positional) and that include static (positional) and dynamic (motion or functional) testsdynamic (motion or functional) tests


Given the questionable reliability and Given the questionable reliability and validity of the tests for the sacroiliac validity of the tests for the sacroiliac joint, the clinician should guard against joint, the clinician should guard against forming a diagnosis based on the results forming a diagnosis based on the results of a few testsof a few tests

Ideally, the diagnosis needs to be based Ideally, the diagnosis needs to be based on the results from a thorough on the results from a thorough biomechanical examination that biomechanical examination that includes pain provocation and static and includes pain provocation and static and dynamic testsdynamic tests


As several recent studies have found As several recent studies have found improved inter-rater reliability in the improved inter-rater reliability in the diagnosis of low back pain when diagnosis of low back pain when using a combination of physical using a combination of physical examination procedures as opposed examination procedures as opposed to a single model approach, it might to a single model approach, it might be logical to assume that a similar be logical to assume that a similar approach would work with the SIJ approach would work with the SIJ


History that indicates SIJ dysfunctionHistory that indicates SIJ dysfunction– A history of sharp pain awakening the A history of sharp pain awakening the

patient from sleep upon turning in bedpatient from sleep upon turning in bed– Pain with walking, ascending or descending Pain with walking, ascending or descending

stairs, standing from a sitting position, or stairs, standing from a sitting position, or with hopping or standing on the involved with hopping or standing on the involved legleg

– A positive straight leg raise at, or near, the A positive straight leg raise at, or near, the end of range (occasionally early in the end of range (occasionally early in the range when hyperacute), pain, and range when hyperacute), pain, and sometimes limitation, on extension and sometimes limitation, on extension and ipsilateral side bending of the trunkipsilateral side bending of the trunk


Systems ReviewSystems Review– Given the number of visceral organs Given the number of visceral organs

in the vicinity of the sacroiliac joint, in the vicinity of the sacroiliac joint, a thorough systems review is a thorough systems review is needed to rule out a visceral source needed to rule out a visceral source for the symptomsfor the symptoms


ObservationObservation– An examination of posture is An examination of posture is

performed to check for the presence performed to check for the presence of asymmetryof asymmetry

– However, as pelvic landmark However, as pelvic landmark asymmetry is probably the norm, asymmetry is probably the norm, ‘positive findings’ are to be ‘positive findings’ are to be expectedexpected


Hip Range of MotionHip Range of Motion– The evidence to demonstrate The evidence to demonstrate

whether hip rotation is limited in whether hip rotation is limited in patients with signs of sacroiliac joint patients with signs of sacroiliac joint dysfunction is inconclusive dysfunction is inconclusive


Palpation of bony landmarksPalpation of bony landmarks– An altered positional relationship An altered positional relationship

within the pelvic girdle should only within the pelvic girdle should only be considered positive if a mobility be considered positive if a mobility restriction of the sacroiliac joint restriction of the sacroiliac joint and/or pubic symphysis is also found and/or pubic symphysis is also found


Weight bearing and non-weight Weight bearing and non-weight bearing kinetic testsbearing kinetic tests– These tests are designed to assess the These tests are designed to assess the

osteokinematics occurring at the sacroiliac osteokinematics occurring at the sacroiliac joint during patient generated movementsjoint during patient generated movements

– The tests assess the mobility of the The tests assess the mobility of the innominate, and the ability of the sacrum innominate, and the ability of the sacrum to nutate (ipsilateral test), and to side to nutate (ipsilateral test), and to side bend (contralateral test)bend (contralateral test)


The short and long-arm tests The short and long-arm tests – These tests are used to confirm or These tests are used to confirm or

refute the findings from the kinetic refute the findings from the kinetic teststests


Sacroiliac Joint Stress Tests– Designed to assess the integrity of

the joint and the surrounding ligaments

– Believed to be sensitive for severe arthritis or ventral ligament tears, although they have been shown to be poorly reproducible

InterventionIntervention

Thus far, the success of Thus far, the success of interventions at this joint has been interventions at this joint has been mixed, due in part to the poor mixed, due in part to the poor reliability with many of the reliability with many of the examinations usedexaminations used

The success of any intervention The success of any intervention depends on the quality and accuracy depends on the quality and accuracy of the examination and the of the examination and the subsequent evaluationsubsequent evaluation


It follows that if the examination gives It follows that if the examination gives an inaccurate diagnosis, the intervention an inaccurate diagnosis, the intervention may have a mixed resultmay have a mixed result

Given that the chosen intervention for Given that the chosen intervention for the sacroiliac joint, like the spine, the sacroiliac joint, like the spine, depends largely on the philosophy or depends largely on the philosophy or background the clinician uses to background the clinician uses to establish the diagnosis, a variety of establish the diagnosis, a variety of diagnoses for the same biomechanical diagnoses for the same biomechanical dysfunction can arisedysfunction can arise


Acute phase goals:Acute phase goals:– Decrease pain, inflammation, and muscle spasmDecrease pain, inflammation, and muscle spasm– Increase weight bearing tolerance, where Increase weight bearing tolerance, where

appropriateappropriate– Promote healing of tissues through sufficient Promote healing of tissues through sufficient

stabilization (may require belt)stabilization (may require belt)– Increase pain-free range of sacroiliac joint motionIncrease pain-free range of sacroiliac joint motion– Regain soft tissue extensibility around the pelvic Regain soft tissue extensibility around the pelvic

regionregion– Regain neuromuscular controlRegain neuromuscular control– Allow progression to the functional stageAllow progression to the functional stage


Functional phase goals:Functional phase goals:– To significantly reduce or to completely To significantly reduce or to completely

resolve the patient’s painresolve the patient’s pain– To restore full and pain-free sacroiliac joint To restore full and pain-free sacroiliac joint

range of motionrange of motion– To integrate the lower kinetic chains into To integrate the lower kinetic chains into

the rehabilitationthe rehabilitation– Complete restoration of gait, where Complete restoration of gait, where

appropriateappropriate– The restoration of pelvic and lower quadrant The restoration of pelvic and lower quadrant

strength and neuromuscular controlstrength and neuromuscular control

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Chapter 27