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Functional Anatomy > Pelvis and SIJ > Flashcards

Pelvis and SIJ Flashcards

1
Q

At what vertebral level is PSIS?

A

S2

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2
Q

What part of the ilium articulates with the sacrum?

A

Auricular Surface

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3
Q

Which way do the facets at the sacral base face?

A

Posteriorly

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4
Q

How many vertebrae make up the coccyx?

A

4

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5
Q

Gender differences in pelvis shape

A

Female: Wider and shorter

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6
Q

What part of pelvis tends to fracture?

A

Pubic rami

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7
Q

Pelvic Chain

A

Connection of axial and peripheral skeleton

  • (B) sacroiliac joints
  • Pubic symphysis
  • Connected pliable ring
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8
Q

SI Joint

A

S1-3 articulating with right and left ilia

Joint is C/ auricular/ boomerang shaped

Surfaces covered with hyaline cartilage

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9
Q

Articular surfaces of SIJ

A

(Hyaline cartilage)
Childhood: Diarthrodial joint (smooth joint surfaces, more movement)

Adulthood: Synarthrodial joint

  • Joint surfaces more rough
  • Aging –> Fibrotic capsule (males lose more motion than females)
  • Irregular joint surfaces correspond to each other (fit together –> stability)
  • 80 y/o, 10% fused
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10
Q

Primary SIJ stabilizers (ligaments)

A

Iliolumbar ligaments
Anterior sacroiliac ligament
Short and long posterior sacroiliac ligaments
Interosseous ligament (internal to joint)

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11
Q

Secondary SIJ stabilizers (ligaments)

A

Sacrospinous ligament

Sacrotuberous ligament

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12
Q

Iliolumbar ligaments

A
  • Ventral, dorsal, and sacral bands
  • TPs of L4,5 to iliac crests/ sacral ala
  • Strong bonds between L5 and ilium
  • Stabilize lumbosacral joint
  • Reinforce anterior side of SIJ
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13
Q

Anterior Sacroiliac Ligaments

A

Thickening of anterior and inferior regions of capsule

- Reinforce anterior side of SIJ

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14
Q

Posterior Sacroiliac Ligaments

A
  • Short posterior
  • Long posterior
  • Reinforce posterior SIJ
  • Fibers blend with sacrotuberous ligament
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15
Q

Interosseous ligament

A
  • Deep to short posterior SI ligaments
  • Fills “gap” between posterior and superior margins of SIJ
  • Strongly and rigidly binds sacrum with ilium
  • Similar in nature to the interosseous ligament in tibfib joint
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16
Q

Sacrotuberous ligament

A
  • PSIS, ILA, and lateral sacrum/ coccyx to ischial tuberosities
  • Blends with fibers of biceps femoris
  • Assists indirectly with SIJ stability (doesn’t actually cross SIJ)
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17
Q

Sacrospinous Ligament

A
  • Ischial spine to lateral border of sacrum
  • Controls lateral/ torsional strain and rotational strain
  • Pelvic floor muscles have attachments to ligament
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18
Q

SIJ Innervation

A
  • Sensory nerves

- Debate re: which exact nerves (L5-S3, dorsal or ventral rami?)

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19
Q

SIJ Dysfunction Symptoms

A
  • Lower lumbar and medial buttocks area
  • Symptoms can refer to posterior thigh
  • Rare that symptoms would refer past knee
20
Q

Pubic symphysis cartilaginous characteristics

A
  • Cartilaginous joint
  • End of each pubic bone is covered with articular cartilage
  • Joint: Fibrocartilaginous disk
21
Q

Pubic Symphysis Ligaments

A

Superior: Thick and dense between tubercles and crest

Posterior: Continuous with periosteum of pubic bones

Inferior: Cross between inferior rami

22
Q

Pubic Symphysis Stabilization

A

Anteriorly: Supported by muscle expansion that forms an anterior “ligament” restricting anterior translation/ shear (TA, rectus abdominus, internal oblique, adductor longus)

23
Q

What other muscle groups play a role in lumbopelvic stability?

A

Abdominals and pelvic floor

Exam: See if activating core/ pelvic floor decreases patient’s symptoms

24
Q

Torque forces on SIJ

A

Innominates: Counterclockwise
Sacrum: Clockwise

25
Shear forces on SIJ
Sacrum, lumbar spine: Caudal | Ilia: Superior
26
Is SIJ stability from form closure or force closure?
Combination of the two
27
Sagittal plane motion of Sacrum
Nutation/ Counternutation | Nutation = base of sacrum nods forward (when ilia move back - coupled with lumbar extension
28
Where is the axis of rotation for nutation/ counternutation?
Medial-lateral at S2 ("Mid-transverse axis)
29
Sacral Torsions
- Named for direction anterior surface of sacrum is facing and the axis of movement R torsion: Anterior surface of sacrum is facing R Axis of movement is either L or R OBLIQUE axis How to determine: One sacral sulcus will be deeper (more anterior) than the other. Examine in prone neutral, exteded, and flexed (child's pose) - Extension: Side that doesn't get deeper is the side sacrum is rotated toward - Flexion: Side that DOES get less deep/ does come back is that side sacrum is rotated toward
30
SIJ Degrees of motion
- Controversial - Potentially decreases with age - 2 degrees of rotation - 2 mm translation in weight bearing - 6 degrees or more of rotation may be unstable
31
Big Three SIJ Muscles
Pelvic Floor Gluteals (*Med) Multifidus
32
Mechanical SIJ/ Pelvic Pain
Symptoms change with change of position or motion E.g.: During pregnancy, pain increases with standing Hx: Trauma - Force through femur and innominate Women - Pregnancy, postpartum, childbirth Gradual - Arthritic disorders Locking - loose body, mismatched surfaces Young adult males - stiffness
33
Non-mechanical SIJ/ Pelvic Pain
Symptoms do not change with change of position or motion | E.g.: Inflammation such as ankylosing spondylitis
34
Hypomobile SIJ Dysfunction
- Pain increases with strain - Golf, tennis - Responds well to treatment
35
Hypermobile SIJ Dysfunction
- Pregnancy related - Athletes - Standing and walking increases pain - Little effect with mobilization - Rest, supports, stability exercises
36
SIJ Pathology Diagnosis
- Historically: Observation and palpation - Gold standard: Videofluoscopic-guided anesthetic block injection into SIJ - Otherwise, look at the role of combining the results of several tests
37
Things to look at when diagnosing SIJ dysfunction:
Standing: - Lumbar spine aligment - Height of pelvic crests - Muscle bulk of gluts - Height of knee creases - Foot alignment Lumbar motion: - AROM, overpressure as appropriate - Assess willingness to move and quality of motion - Assessment for centralization with repeated motion testing - If lumbar motion increases pain, consider lumbar to be more likely source of sxs Palpation Leg Length Difference (true vs. apparent) Supine Active Straight Leg Raise Cluster of SIJ tests
38
Long Sitting Test
Test for true leg length difference (hook lying, bridge, supine - assess, long sitting- assess) If leg lengths still look different in sitting - true LLD
39
Supine Active Straight Leg Raise
1. Supine active SLR - Pt's sxs are produced 2. Supine active SLR with compression at pelvis from hands, or use of belt - If patient's sxs are less/ eliminated - positive test - Indicates hypermobility at pelvic ring *Raise leg on symptomatic side
40
Cluster of SIJ tests
- 6 out of 6 tests negative for reproduction of pt's symptoms: sensitivity = 100% - Two out of four positive for production of pt's symptoms: Specificity = 78% Tests: 1. Distraction test 2. Thigh thrust 3. Compression test 4. Sacral thrust 5. (Gaenslon's - each side)
41
Distraction Test
1. Pt. supine 2. Identify sxs 3. Force applied in lateral-posterior direction on ASIS 4. Hold for 30 seconds, then apply a quick force in direction of applied pressure (unless they're already feeling sxs) Positive: Production of comparable sign (pain usually)
42
Thigh Thrust Test
(AKA Ostagaard, sacrotuberous stress test, POSH test) 1. Pt supine 2. Identify sxs at rest 3. Stand on side opposite of sxs 4. Hip on symptomatic side flexed to 90 5. Examiner places hand under sacrum 6. Downward pressure applied through femur (Shearing innominate against sacrum) Positive: Reproduction of comparable sign
43
Compression Test
1. Pt sidelying on asymptomatic side 2. Identify sxs at rest 3. Cup iliac crest and apply downward force through ilium (proximal to greater trochanter) 4. Hold 30 seconds Positive: Production of comparable sign
44
Sacral Thrust
1. Pt prone 2. Identify resting sxs 3. Palpate 2nd or 3rd spinous process of sacrum 4. Vigorous and repeated downward force to sacrum (up to 6 thrusts) - Do one thrust slowly first to assess whether you should do thrusts Positive: reproduction of comparable sign during downward pressure
45
Gaenslon's Test
1. Pt lies close to edge of plinth 2. One limb dropped of the edge of plinth, other limb flexed toward chest 3. Examiner applies counter pressure to both limbs (--> torque on pelvis) Positive: Reproduction of comparable sign during downward pressure
46
Treatment of SIJ Dysfunction
If patient needs: - Mobility: Manual techniques - Stability: SIJ belt, active stability with muscle contraction

Functional Anatomy (14 decks)

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