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MSK T3 > SI > Flashcards

SI Flashcards

1
Q

What is the sacroiliac (SI) joint?

A

The sacroiliac joint is the articulation between the auricular surfaces of the sacrum and ilium. It is a synovial joint with one surface covered by hyaline cartilage and the other by fibrocartilage.

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2
Q

How do the ridges on the articular surfaces and the shape of the sacrum contribute to SI joint stability?

A

The ridges on the articular surfaces and the ‘keystone’ shape of the sacrum (wide superiorly and narrow distally) enhance stability in the SI joint.

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3
Q

What are some evolutionary adaptations of the pelvis for bipedal movement and lumbopelvic stability?

A

• Flaring of the ilia into the sagittal plane for more lateral attachment of the gluteus medius (primary pelvic stabilizer).
• Larger attachment site for gluteus maximus (originating from sacrum and sacrotuberous ligament), aiding forward propulsion in gait.

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4
Q

What role do ligaments play in stabilizing the sacroiliac joint?

A

Thickened ligaments stabilize the sacroiliac joint both anteriorly and posteriorly, especially on the dorsal side of the sacrum.

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5
Q

What is the main function of the posterior sacroiliac ligament?

A

It acts as the primary posterior stabilizer of the SI joint, attaching the sacrum to the ilium, and is located deep to the sacrotuberous ligament.

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6
Q

What is the attachment and function of the sacrospinous ligament?

A

The sacrospinous ligament attaches from the ischial spine to the sacrum/coccyx.

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7
Q

Where does the sacrotuberous ligament attach?

A

It attaches from the ischial tuberosity to the posterior superior iliac spine (PSIS), sacrum, and coccyx.

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8
Q

What is the function and attachment of the interosseous sacroiliac ligament?

A

This ligament provides stabilization by attaching the sacrum to the ilium.

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9
Q

What is the iliolumbar ligament and where does it attach?

A

The iliolumbar ligament attaches from L4-L5 to the iliac crest, providing additional stability.

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10
Q

What is the primary anterior stabilizer of the SI joint?

A

The anterior sacroiliac ligament, which attaches the sacrum to the ilium.

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11
Q

What joints articulate in the sacroiliac joint?

A

The auricular surfaces of the sacrum and ilium.

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12
Q

What type of joint is the sacroiliac joint, and what are its surface coverings?

A

It’s a synovial joint with one surface covered in hyaline cartilage and the other in fibrocartilage.

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13
Q

How do the articular surface ridges and keystone shape of the sacrum contribute to the sacroiliac joint?

A

They provide stability to the joint, with the sacrum’s wide superior base and narrower distal end enhancing joint stability.

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14
Q

How has human evolution affected the pelvis for bipedal movement?

A

The ilia flare into the sagittal plane, allowing lateral attachment for gluteus medius and a larger attachment for gluteus maximus, aiding in lumbopelvic stability and forward propulsion.

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15
Q

What role do the sacroiliac ligaments play in joint stability?

A

Thickened ligaments stabilize the sacroiliac joint anteriorly and posteriorly, especially on the dorsal side of the sacrum.

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16
Q

Name the primary posterior stabilizer of the sacroiliac joint.

A

The posterior sacroiliac (dorsal) ligament, attaching the sacrum to the ilium.

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17
Q

What is the attachment and function of the sacrospinous ligament?

A

It attaches the ischial spine to the sacrum/coccyx, contributing to sacroiliac joint stability.

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18
Q

Where does the sacrotuberous ligament attach, and what does it stabilize?

A

It attaches the ischial tuberosity to the PSIS, sacrum, and coccyx, stabilizing the posterior sacroiliac joint.

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19
Q

Which ligament is the primary anterior stabilizer of the sacroiliac joint?

A

The anterior sacroiliac (ventral) ligament, connecting the sacrum to the ilium.

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20
Q

What are the attachments for the iliolumbar ligament?

A

It attaches from L4-L5 to the iliac crest, providing additional support to the lumbopelvic region.

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21
Q

Which nerves provide innervation to the sacroiliac joint?

A

Branches of the sacral plexus, dorsal rami of S1 and S2, superior gluteal nerve branches, and obturator nerves.

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22
Q

How can irritation of the sacroiliac joint affect nearby nerves?

A

It can irritate the L4-L5 spinal nerves, potentially causing dermatomal pain referral characteristic of L4-L5.

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23
Q

What are the primary biomechanical functions of the sacroiliac (SI) joint?

A

The SI joint absorbs and distributes ascending forces from the ground and descending gravitational forces, acting as a stress reliever by absorbing shock and shear from movement involving the spine and both lower extremities.

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24
Q

Why does the SI joint primarily need to be stable?

A

It serves as a convergence point of high loads with a small range of motion, necessary to absorb shock during gait and to aid in childbirth.

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25
Q

How does lumbar movement influence the sacrum?

A

The sacrum directly articulates with L5 via the intervertebral disc, so lumbar movement directly impacts the sacrum.

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26
Q

What are the two primary movements of the sacrum relative to the ilia?

A

Nutation (sacral flexion) and counternutation (sacral extension).

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27
Q

Describe nutation and its significance.

A

Nutation is sacral base movement anteriorly with the apex moving posteriorly; it’s a closed-packed position for weight-bearing activities, providing posterior stability to the SI joint.

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28
Q

Describe counternutation and when it typically occurs.

A

Counternutation is sacral base movement posteriorly with the apex moving anteriorly, typically occurring in a non-weight-bearing position, such as lying supine.

29
Q

What is the range of motion (ROM) for the combined movements of nutation and counternutation?

A

2-4 degrees of rotation.

30
Q

Define form closure.

A

Form closure is the stability a joint receives from its bony articulation, theoretically achieving 100% stability without external forces, although this would eliminate joint mobility.

31
Q

What is force closure, and why is it important?

A

Force closure is joint compression from myofascial and ligamentous tension providing lateral force, essential for bearing vertical loads, especially during unilateral lower extremity loading like in gait.

32
Q

How does nutation contribute to force closure?

A

Nutation tightens the dorsal ligaments, increasing SI joint compression to prepare for weight-bearing stability.

33
Q

Why is force closure critical during unilateral loading of the lower extremity?

A

Unilateral loading (e.g., during gait) increases shear forces at the SI joint, requiring additional stabilization from force closure to prevent joint strain.

34
Q

What deep core muscles are crucial for stabilizing the lumbar spine and pelvis?

A

Multifidi, Transverse Abdominis, Respiratory diaphragm, and Pelvic diaphragm (pelvic floor).

35
Q

How do the deep core muscles contribute to lumbopelvic stabilization?

A

They must be neurologically facilitated and fire in synergy to stabilize the lumbopelvic region before extremity movement.

36
Q

List common reasons for dysfunction in core musculature.

A

Prolonged posture and imbalance, back pain, pelvic pain, surgery/injury, nerve impingement (intercostal, iliohypogastric, ilioinguinal), pregnancy/childbirth, obesity, disuse, and rib/thoracic spine immobility.

37
Q

What factors affect SI joint stability?

A

Lumbopelvic instability, foot and ankle mechanics, thoracic spine immobility, hip immobility, pregnancy, leg length discrepancy, and scoliosis.

38
Q

Why is the gluteus medius important for pelvic stability?

A

It helps maintain pelvic stability during gait, reducing shear stress on the SI joints.

39
Q

What happens if the core and glutes lack lumbopelvic control?

A

Iliacus and psoas may compensate, leading to anterior pelvic tilt, hyperlordosis, nutation, SI joint hypomobility, and abnormal sacrum-ilium movement.

40
Q

How do abnormal foot and ankle mechanics impact SI joint stability?

A

Overpronation or oversupination fails to absorb forces efficiently, passing excessive stress to the SI joints through the kinetic chain.

41
Q

What thoracic spine movements are important for overall joint health?

A

Extension, rotation, and lateral flexion.

42
Q

How does thoracic spine rigidity affect lumbar and SI joint stability?

A

It may cause compensatory lumbar movement, adding shear stress to SI joints and altering diaphragm and core mechanics.

43
Q

Why is hip mobility essential for SI joint stability?

A

Restricted hip movement may cause compensatory lumbar mobility, leading to lumbar spine instability and increased shear stress on SI joints.

44
Q

What postural dysfunction in the hips may affect SI joint stability?

A

Lower cross syndrome can lead to lumbar compensation and weakness in muscular slings needed for SI joint force closure and stability.

45
Q

What are the effects of pregnancy on the sacroiliac (SI) joints?

A

Postural changes, muscular imbalance, hormonal changes causing joint laxity, nerve stretching/damage, and damage to core and pelvic floor muscles.

46
Q

How does pregnancy-related center of gravity change affect the SI joints?

A

It leads to excessive lordosis, anterior pelvic tilt, and sacral nutation, initially enhancing force closure but eventually causing degeneration, inflammation, and ligament laxity due to prolonged stress.

47
Q

What muscle imbalances are common during pregnancy due to postural changes?

A

Shortened hip flexors and lengthened abdominals and hip extensors, which can weaken over time and reduce force closure and lumbopelvic stability.

48
Q

How do hormonal changes during pregnancy impact the SI joints?

A

They cause ligament laxity, increasing movement and the risk of degradation and inflammation in the SI joints to facilitate childbirth.

49
Q

What impact does childbirth have on the pelvic floor muscles and pudendal nerve?

A

The pelvic floor muscles stretch and often tear, weakening them and possibly inhibiting their function, which affects overall core stability.

50
Q

List some other conditions that can cause SI joint dysfunction.

A

Connective tissue disorders, osteoarthritis, rheumatoid arthritis, ankylosing spondylitis, and trauma.

51
Q

What is the treatment focus for SI joint dysfunction from conditions like arthritis or connective tissue disorders?

A

Addressing tissue impairments, optimizing biomechanics, reducing joint stress, and strengthening surrounding musculature for increased stability.

52
Q

What are common signs and symptoms of SI joint dysfunction?

A

Pain over SI joints (inferomedial to PSIS), tenderness on palpation, low back pain, radiating leg pain (L4-L5 dermatomal pattern), pain when turning in bed, and pain with load transfer (e.g., sit-to-stand, standing on one leg).

53
Q

Which dermatomal patterns are associated with referral to the lower extremity in SI joint dysfunction?

A

L4-L5 dermatomal patterns.

54
Q

What are common compensation patterns seen in SI joint dysfunction?

A

Compensation patterns often involve the piriformis, iliopsoas, adductors, pelvic floor muscles, and fibrosing of the joint.

55
Q

Why do SI joint dysfunction tests have poor specificity and sensitivity?

A

The minimal movement at the SI joint makes specific tests for dysfunction unreliable, with poor interrater reliability; three or more positive tests are often needed for diagnosis.

56
Q

What is the gold standard for diagnosing SI joint pain?

A

An intra-articular injection of anesthetic under radiological imaging guidance.

57
Q

What does a positive Stork test indicate?

A

Absence of proper pelvic mechanics or lack of posterior rotation of the non-stance leg innominate during single-leg stance.

58
Q

How is the Forward Bend test performed, and what indicates a positive result?

A

With hands on the iliac crests and thumbs under PSIS, observe PSIS movement during forward bending. Unequal cranial movement of PSISs indicates restriction.

59
Q

Describe the Femoral Shear Test (Thigh Thrust) and its positive sign.

A

Flex the hip to 90 degrees, stabilize the sacrum, apply vertical pressure to the femur; reproduction of SI joint pain is positive.

60
Q

How is the Fortin Finger Test conducted, and what does a positive result indicate?

A

The patient points to pain located inferomedial to the PSIS, indicating possible SI joint involvement.

61
Q

Describe the FABER’s test and what a positive result indicates.

A

Patient’s hip is placed in figure-4 position; point-specific pain at the SI joint suggests dysfunction.

62
Q

How is Gaenslen’s Test performed, and what does a positive result indicate?

A

Patient flexes one hip maximally while the other extends off the table; SI joint pain in the extended hip suggests dysfunction.

63
Q

What is the purpose of the Active Straight Leg Raise test?

A

To assess SI joint pain reproduction with leg raise; if core activation reduces pain, stabilization exercises may be beneficial.

64
Q

What does a positive SI Joint Compression Test indicate?

A

Point-specific SI joint pain during downward pressure on the iliac crest, testing posterior SI ligaments.

65
Q

Describe the SI Joint Distraction Test and a positive result.

A

Apply downward and outward pressure on the medial ASIS to distract the anterior SI joint; SI joint pain indicates dysfunction.

66
Q

What does a positive Prone Straight Leg Raise test indicate for SI joint dysfunction?

A

Pain during the leg raise that decreases with SI joint stabilization suggests benefit from stabilization exercises.

67
Q

Why might functional movement tests be useful in diagnosing SI joint pain?

A

Movements like squats, lunges, or step-downs may reproduce SI joint pain, aiding in diagnosis.

68
Q

What is the general treatment approach for SI joint pain?

A

Address postural alignment, muscle length and strength, treat tissue impairments, optimize biomechanics, and provide exercise and mobility interventions.

69
Q

What additional treatments may be recommended for SI joint dysfunction?

A

Joint mobilization, muscle energy techniques, exercise prescriptions, physiotherapy referral, orthotics for foot alignment, and lumbopelvic braces if needed.

MSK T3 (5 decks)

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