Pelvis Flashcards
Lumbar-Pelvic-Hip Complex
One mechanical unit
4th & 5th lumbar joints (4 apophyseal joints)
Sacrum (2 synovial)
Two Acetab-Fem joints
Pubic symphysis
The lumbar-pelvic-hip complex is the centre for:
Static weight bearing
Normal biomechanics
Posture
Pelvis
Bony ring formed by two innominates, the sacrum, and the cavity formed by them
Pelvis is the keystone of
postural aligment
Sacrum is the keystone of
the pelvis
Sacrum is the seat of
Transverse centre of gravity
Most important mechanical function of pelvic girdle
Transmit weight of upper body to lower limbs
Pubic symphysis
Cartilaginous joint with fibrocartilage disc
Affected by SIjt mobility
Force of body weight does what to sacrum?
Separates sacrum from ilia
Pushes first sacral segment into nutation/flexion
Sacrococcygeal joint
Fused symphysis with fibrocartilage disc. Occasionally synovial
Flexion/extension (no lateral flexion)
Sacroiliac Joint
Part synovial (C-shaped – anterior and inferior)
Part syndesmosis
Sacral surface concave and hyaline
Ilium convex and fibrocartilage
Function of SI joint
Transfers weight from spine to lower limbs
Provides elasticity to pelvic ring
Decreases transfer of jarring forces from legs to spine.
SI jt: resting position
Neutral
SI jt: Capaular pattern
Pain when joints are stressed.
SI: close pack
Nutation
SI: loose pack
Counter nutation
Anterior SI ligament
Anterior lateral sacrum –>
Margin of auricular surface of ilium, preauricular sulcus
Prevents over outflare
Short posterior SI ligament
Horizontal (ish)
Transverse tubercles of sacrum –>
Ilial tuberosity
Limits all movement, especially inflare
Long posterior SI ligament
PSIS –> sacrum
Oblique
Limits inflare/ anterior rotation
Sacrospinous ligament
Outer edge of sacrum and coccyx –>
Spine of ishium
Creates border between greater and lesser sciatic notch
Prevents rotation of ilium past sacrum
Sacrotuberous ligament
Lower transverse sacral tubercle, upper coccyx –> Ischial tuberosity
Limits nutation and posterior inominate nutation.
Provides vertical stability.
Can trap pudental nerve
Iliolumbar ligament
TVP of L5 –> upper margin of ilium
Maintains lumbosacral stability by limiting lateral flexion
In a neutral pelvis, where are the ASIS’s?
Same vertical plane as the pubic symphysis
Pelvic tilt
Angle between a line joining ASIS and PSIS and a horizontal line
7-15º
Lumbosacral Angle
Junction between middle of L5 vertebral body and the sacrum
140º
Lumbar lordotic curve
Angle formed when a line is drawn from the top of L1 vertebral body and the base of the L5 vertebral body
50º
Sacral angle
Angle formed when a line is drawn from the top of the sacral base and compared to the horizon
30º
Pelvic angle
Angle formed when a line is drawn from S2 to the top of the pubic symphysis and compared to the horizon.
30 degrees
Sacral locking
AKA nutation
Top of sacrum shifts forward, Ilia approximate, Ischial tuberosities move apart.
More stable that counternutation
What ligaments control nutation?
Sacrospinous
Sacrotuberous
anterior interosseus and/or anterior SI ligaments
Sacral unlocking
Aka counternutation
Top of sacrum shifts forward, ilia move apart, Ischial tuberosities approximate
Less stable than nutation
What limits counternutation?
Posterior SI ligaments, supported by multifidis
When the sacrum counternutation what direction does its articular surface move?
Anterior-superior
Stability of the sacrum is determined by what two forces:
Form closure and force closure
Form closure
Sacral stability achieved by the passive “locking in” of pelvic structures.
Force closure
Sacral stability achieved through the tension generated by muscles, joint capsule, and other intrinsic forces, love the sacrum into nutation.
Upslip
Both ASIS and PSIS on one ipsilaterally higher.
May have short leg on down side or muscle spasm in lumbar.
MOI usually traumatic (sudden landing on one leg)
Outflare/Inflare
Unilateral or bilateral
Movement of innominates outward and inward (around vertical axis in transverse plane)
Can present with ASIS not being equidistant from midline.
Outflare
ASIS more lateral
PSIS more medial
Often presents with posterior rotation of same innominate
Inflare
ASIS more medial
PSIS more lateral
Often presents with anterior rotation of same innominate
Down slip
Both ASIS and PSIS unilaterally lower
Often traumatic MOI
Anterior torsion of sacrum
Pathological unilateral nutation
May result in spinal scoliosis or altered functional leg length
Anteriorly rotated innominate
PSIS higher than ASIS on affected side
Most often after forced diagonal pattern. May be combined with sacral torsion.
Unilateral movement of innominate with hip flexion
Standing single leg raise
Landmark sacral spine and PSIS
PSIS should move down
Landmark isch tube and sacral spine
Ischial tubes should move lateral and inferior
Seated forward flexion
Landmark base of sacrum and inferior lateral angles.
Check for symmetry (ant-post)
Bilateral extension of the innominate with hip extension
Standing trunk extension
Landmark PSIS’s. They should move inferiority
Bilateral sacral nutation with partial hip flexion
Standing slow forward flexion
Landmark PSISs
First 45 degrees: nutation
After 60 degrees: counternutation
Trendelenburg Sign
Stand on one leg
Test: weakness or instability of hip abductors (glute med) on stance side
Positive: pelvis drops on nonstance side
Stork Standing Test
Mod tree pose. (Eyes open, closed)
Watch for lateral force applied to knee
Tests for: integrity of pelvic joints; stability and proprioception of pelvis and legs.
Positive: pain in any pelvic joint; can’t balance
Flamingo
Stand on one leg. Left foot just barely off ground
Tests for lesion in pubic symphysis or SI joint.
Positive: pain in either joint. Pelvis on stance side rotates.
Gillet’s test
Aka sacral fixation test, ipsilateral posterior rotation test
Standing hip flexion
Testing hypomobile SI jt.
Positive: PSIS moves minimally, or upward
Ipsilateral anterior rotation test
Standing hip extension
(If can’t bring hip into flexion)
Palpate PSIS and sacrum
Test: hypomobile SI jt
Positive: PSIS doesn’t move, or moves
Inferiority
Ipsilateral prone kinetic test
Tests for : SI jt hypomobility, possible posterior rotation/outflare
One thumb on PSIS, the other on sacrum
Positive: hip extension elicits abnormal PSIS movement
Squish test
Supine
Tests: posterior SI ligament integrity
Push ASIS’s down and in at 45 degrees
Positive: pain
Gapping test
Transverse anterior stress test
Supine
Tests anterior SI ligament.
Push ASIS’s down and out
Positive: pain in glutes or posterior leg
Thomas test
Supine, one leg off table
Tests for hip flexion contracture.
Positive:
Iliopsoas: thigh off table
Quad: knee extension
TFL/ITB: J stroke
Obers Test
Side lying
Tests TFL/ITB
Stabilize hip. Abduct and extend top leg; allow to lower.
Positive: leg doesn’t drop; pain in hip (trochanteric bursitis).
Sharp, bright, burning pain
Nerve pain
Deep, boring, localized pain
Bone
Diffuse, aching, poorly localized, possibly referred pain
Vascular
Dull, aching, hard to localize pain. Aggravated by movement and stretch.
Muscle pain.
Somatic pain
Severe chronic or aching pain inconsistent with injury or pathology.
