II: Biomechanics Of The Pelvis (PART 2/2 - evaluation) Flashcards
Landmarks to observe in posture
- iliac crests
- PSISs
- greater trochanters
- gluteal folds
- pelvic tilt
What boney landmarks are you palpating for in prone?
- Iliac crests
- PSIS
- sacral base, borders and apex
- coccyx
Dr.’s thumbs on PSIS & sacral tubercle and Pt. flexes ipsilateral hip . This is a Gillet’s test for assessing:
- upper joint flexion
- Dr’s thumbs should approximate as ilium flexes on the sacrum and the PSIS move posteriorly and inferiorly
Dr.’s thumbs on PSIS & sacral tubercle Pt. flexes contralateral hip. This is a Gillet’s test for assessing:
- upper joint extension
- Dr’s thumbs should separate as sacrum counternutates relative to the ilium and the sacral tubercle moves inferiorly
Dr.’s thumbs on sacral tubercle or side of sacral apex & area of PIIS. Pt. flexes ipsilateral hip. This is a Gillet’s test for assessing
- lower joint flexion
- Dr’s thumbs should separate as the ilium flexes on the sacrum and the PIIS moves inferiorly and anteriorly
Dr.’s thumbs on sacral tubercle or side of sacral apex & area of PIIS. Pt. flexes contralateral hip. This is a Gillet’s test for assessing
- lower joint extension
- sacral contact thumb should move inferiorly relative to PIIS contact as sacrum counternutates relative to ilium
Motion palpation for standing is called
Gillets test
What are the major mechanical functions of the pelvis?
attach spine to and transfer weight to lower extremity
shock absorption
gyroscopic action during gait
important in birth process in females
The pelvis consists of what 3 joint complexes?
2 SI joints
1 pubic symphysis
What joint classification is the pubic symphysis?
fibrocartilaginous amphiarthrosis
The articular surface of the SI joint is primarily in what plane?
sagittal (about 10 degrees to sagittal)
Describe the articular surface of the SI joint?
auricular shaped
cephalad portion = “upper joint”
caudad portion = “lower joint”
Describe the iliac surface of the SI joint?
central convex ridge covered in fibro cartilage
What is the large, rough, bony surface posterior to the SI joint that serves for ligamentous attachment?
iliac tuberosity
Describe the sacral surface of the SI joint?
central concavity that is covered in hyaline cartilage that is 3 times thicker than firbocartilage of iliac surface
What are the intrinsic ligaments that bind the sacrum to the ilium?
anterior superior ligaments
anterior inferior ligaments
posterior sacroiliac ligaments
interosseous SI ligaments
What are the extrinsic ligaments that bind the sacrum to the iliac?
sacrotuberous
sacrospinous
iliolumbar
What muscles are related to pelvic biomechanics?
multifidis, erector spinae via SI ligament
hamstrings, gluteus max and piriformis vis scarotuberous l.
psoas via anterior joint capsule
quadratus lumborum vis iliolumbar l.
Describe the innervation of the SI joint?
exact innervation is debated but has both pain and proproceptive innervation
What are the most functionally important anatomy features of the SI joint?
it is synovial diarthrodial
auricular shaped joint surface
corresponding groove/ridge on joint surface
locking sacral wedge shape, interlocking sacral S configuration
strong posterior SI ligaments resist distraction and translation
muscles that insert into joint capsule and pelvis add stability
Describe SI joint development at birth?
joints are undeveloped, smooth, flat and glide in any direction
start to develop with walking
Describe SI joint development during teens?
roughening of surfaces, development of grooves and ridges
this occurs more pronounced in males than females
Describe SI joint development in the 3rd and 4th generation of development?
joint surfaces become irregular
enlargement of iliac tuberosity
joint surfaces begin eroding
possible osteoarthritis on iliac surface
Describe SI joint development in the 5th and 6th generation?
joint surface continues to become more irregular
possible osteoarthritis developing on sacral surface
osteoarthritis continuing on iliac surface
development of joint adhesions, osteophytes and fusion
Describe SI joint development in the 7th decade and beyond?
interarticular adhesions
high prevalence of bony ankylosis (fusion)
Describe the trends seen in the fusion of the SI?
more prevalent in males (27.7% vs 2.3% in females)
age dependent in males with 46.7% of those over 80 years
fusion occurs mainly in the superior part of the joint
What is the major static function of the pelvis?
to bear weight via two weight bearing arches
What are the gravitational forces acting on the posterior arch of the pelvis and what resists them?
- down and posterior resisted by wedge shaped sacrum
- down and anterior resisted by “S” shaped joint, posterior ligament, interosseous ligaments and sacrotuberous ligaments
What is the function of the anterior arch of the pelvis which is formed by the pubic rami?
connect posterior arches and act as a compression strut
What anatomy features of the SI joint promotes stability
(form closure)?
- wedge shape of the sacrum
- interlocking groove (sacrum) and ridge (ilium)
- S-shaped joint surface
What supports the SI joints (force closure)?
tension in muscles
ligaments
thoracolumbar fascia
What is sacral nutation?
when the sacral base moves anterior and inferior
What happens to the lumbosacral region when the sacrum nutates?
the lumbosacral region extends
What is sacral counternutation?
when the sacral base moves posterior and superior
What happens to the lumbosacral region when the sacrum counternutates?
the lumbosacral region flexes
How much does the pelvic joint mobility increase during pregnancy?
2.5 times increase
What happens to the sacrum during delivery/childbirth?
it nutates and counternutates
What happens to the pubic symphysis during pregnancy?
it increases in width by 4-9mm
What happens to the sacrum during inspiration?
the sacrum counternutates due to the spine flattening (all curves decrease)
What happens to the sacrum during expiration?
the sacrum nutates (all spinal curves increase)
When the PSIS moves posterior and inferior, what ilial sagittal movement occurs?
flexion
When the PSIS moves anterior and superior, what ilial sagittal movement occurs?
extension
What is the static malpostion where ilium is in flexion?
PI ilium
flexion malposition
- θx
What is the static malposition where ilium is in extension?
AS ilium
extension malposition
+ θx
SI joint motion is named according to what?
the ilium movment relative to the sacrum no matter which bone is actually moving (this will be on midterm per Partna)
In what type of SI joint motion does the ilium flex relative to the sacrum?
flexion
In what type of SI joint motion does the sacrum nutate relative to the ilium?
flexion
In what type of SI joint motion does the ilium extend relative to the sacrum?
extension
In what type of SI joint motion does the sacrum counternutate relative to the ilium?
extension
Motion palpation for standing include:
Gillet’s Test
Motion palpation for sitting include:
P-A glide
Sacral Push
Iliac Shear
Leg Flare
Piedau’s Test
In sacral push, patient extends back and sacral base should move:
Anterior
What is the Doc contact for Piedau’s Test and what is the patient doing?
Doc’s thumbs contacting either side of sacral apex and fingertips on PSIS. Patient bends forward.
What is normal movement in Piedau’s Test?
Separation of PSIS and sacral base (doc’s digits move apart), indicating the sacral base moves posteriorly relative to ilia.
In Piedau’s Test, what would be a sign of hypomobility?
If one PSIS starts inferior and ends up superior. Because SI joint not free to glide; ilium must move farther to make up for lack of SI motion.
Why do PSIS separate slightly in Piedau’s Test?
Sacrum wedges itself more tightly between ilia (posterior and superior movement) and it pushes PSIS laterally.
Name the Doc contact for SI joint provocation: extension
1 handed: PSIS
Two-handed: PSIS and sacral apex
Name the Doc contact for SI joint provocation: flexion
1 handed: Sacral base
Two-handed: Sacral base & ischial tuberosity
Name the Doc hand contact for side posture: extension
1 handed: PSIS
2-handed: PSIS & anterior hip area
Name the Doc hand contact for side posture: flexion
1 handed: ischial tuberosity
2-handed: ischial tuberosity & ASIS
Why does leg length evaluation get a bad rep?
- Prone to examiner error
- complicated by variety of factors
- small discrepancies are probably unreliable
What is the % prevalence in population with anatomic leg length inequality? And what is the average in mm?
90%
5.2mm
What positions do you check leg length in?
Prone straight legs to check malleoli & bent knees (90˚) to check tibia/fibula length
Supine with straight legs to compare malleoli & bent knees (Allis Test) to look for tib/fib as well as femoral inequality
Sit-up test
What is they key point to remember about the sit-up test?
It doesn’t reveal which SI joint is dysfunctional, only their relative positions.
When sitting, acetabular anteriority of the flexed ilium makes the _______, while acetabular posteriority of the extended ilium makes the leg ________.
lengthen; shorten
Because: During the sit-up test, the leg lengthens on the flexed (PI) side and/or shortens on the extended (AS) side.
When supine, acetabular superiority of the flexed ilium makes the leg appear _____ while acetabular inferiority of the extended ilium makes the leg appear _____.
Shorter; longer
Because: During the sit-up test, the leg lengthens on the flexed (PI) side and/or shortens on the extended (AS) side.
A flexed ilium positions the acetabulum more _______ and _________. An extended ilium positions the acetabulum more ______ and ______.
Cephalon and anterior; caudate and posterior
Because: During the sit-up test, the leg lengthens on the flexed (PI) side and/or shortens on the extended (AS) side.
During the sit-up test, the leg lengthens on the ___________ side and/or shortens on the __________ side.
flexed (PI)
extended (AS)
What are 3 possible outcomes of the sit-up test (for leg length)?
- Relative leg length stays the same: anatomical inequality
- relative leg lengths switch: functional inequality
- other relative change: both anatomic and functional inequality
Patient’s legs start even, right leg becomes longer after sit-up. What is this outcome?
Both functional and anatomic inequality
Patient’s right leg starts shorter, becomes even shorter after sit-up. What is this outcome?
Both functional and anatomic inequality
Patient’s right leg starts shorter, legs become even after sit-up. What is this outcome?
Both functional and anatomic inequality
Patient’s right leg starts shorter and becomes longer by the same amount after sit-up. What is this outcome?
functional inequality
Patient’s right leg starts shorter and stays shorter after sit-up. What is this outcome?
anatomical inequality
What are the ways to check out pubic symphysis?
Static: A-P and S-I (painful?)
Motion: A-P and S-I on rami, pt. leg elongation to palpate shearing movement
X-Ray: pt. standing on 1 leg
Describe a PI (flexed ilium)
Taller obturator foramen and taller innominate
Describe an AS (extended ilium)
Shorter obturator foramen and shorter innominate
Describe an IN (externally rotated ilium)
wider ilium
Describe an EN (internally rotated ilium)
narrower ilium
What will happen to R and L leg lying down and then in sit up test?
(You are viewing patient from behind.)
Lying down: Left leg is short, right leg is long
Sit up: Left leg is long, right leg is short
Name your findings for this standing presentation of anatomical leg length inequality (LLI) and/or pelvic dysfunction/subluxation. (You are viewing patient from behind.)
- Pelvis makes left leg functionally shorter by left ilium flexion and/or right leg longer by right ilium extension
- Functional LLI
- Functionally short left leg has farther to reach for their foot to get to the floor, making left iliac crest low (caudad)
- Functional scoliosis
(These lines represent the palpatory locations of the iliac crests and greater trochanters.
If the lines are parallel, there is no pelvic distortion and no functional LLI.
If they are not parallel, then there is pelvic distortion and functional LLI.)
Name your findings for this standing presentation of anatomical leg length inequality (LLI) and/or pelvic dysfunction/subluxation. (You are viewing patient from behind.)
- Anatomical LLI
- Overcompensation of the pelvis: Pelvis makes left leg functionally longer by left ilium extension and/or right leg shorter by right ilium flexion
- Functional LLI
- Functional scoliosis
(These lines represent the palpatory locations of the iliac crests and greater trochanters.
If the lines are parallel, there is no pelvic distortion and no functional LLI.
If they are not parallel, then there is pelvic distortion and functional LLI.)
What will happen in sit up test with R and L leg?
(You are viewing patient from behind.)
Left leg shortens
Right leg lengthens
Name your findings for this standing presentation of anatomical leg length inequality (LLI) and/or pelvic dysfunction/subluxation. (You are viewing patient from behind.)
- Complete compensation by the pelvis for an anatomical LLI: Pelvis makes left leg functionally longer by left ilium extension and/or right leg shorter by right ilium flexion “Smart pelvis”
- Reduces stress in the lumbar spine, but SI joints may be symptomatic due to dysfunction
- May get a functional scoliosis after SI treatment unless they get a heel lift
(These lines represent the palpatory locations of the iliac crests and greater trochanters.
If the lines are parallel, there is no pelvic distortion and no functional LLI.
If they are not parallel, then there is pelvic distortion and functional LLI.)
What is R vs L leg length in lying down position? In sit up?
(You are viewing patient from behind.)
Left side will shorten
Right side will lengthen
Name your findings for this standing presentation of anatomical leg length inequality (LLI) and/or pelvic dysfunction/subluxation. (You are viewing patient from behind.)
- Anatomical LLI
- Partial compensation of pelvis: Pelvis makes left leg functionally longer by left ilium extension and/or right leg shorter by right ilium flexion
- Functional LLI
- Functional scoliosis
(These lines represent the palpatory locations of the iliac crests and greater trochanters.
If the lines are parallel, there is no pelvic distortion and no functional LLI.
If they are not parallel, then there is pelvic distortion and functional LLI.)
Name your findings for this standing presentation of anatomical leg length inequality (LLI) and/or pelvic dysfunction/subluxation. (You are viewing patient from behind.)
- Anatomical LLI
- No pelvis compensation
- Functional scoliosis
(These lines represent the palpatory locations of the iliac crests and greater trochanters.
If the lines are parallel, there is no pelvic distortion and no functional LLI.
If they are not parallel, then there is pelvic distortion and functional LLI.)
Name your findings for this standing presentation of anatomical leg length inequality (LLI) and/or pelvic dysfunction/subluxation. (You are viewing patient from behind.)
- Normal
- No anatomical LLI
- No functional LLI
- No pelvic distortion
(These lines represent the palpatory locations of the iliac crests and greater trochanters.
If the lines are parallel, there is no pelvic distortion and no functional LLI.
If they are not parallel, then there is pelvic distortion and functional LLI.)
What are distortion pattern findings for Extension (AS) malposition?
PSIS less prounounced
Low ASIS
Long functional leg
Functionally long leg shortens during sit-up test (not necessarily shorter than other leg, just shorter than it was at start)
High (cephalon) iliac crest and PSIS (standing)
Low (caudad) iliac crest (prone or supine)
High gluteal fold (standing)
Plum line falls over the same side as the AS ilium
Possible functional lumbar scoliosis to opposite side
Thigh extends further
Heel approaches buttock easier (prone)
Pain in lateral knee and TFL
Possible referred pain in buttock, posterior thigh, groin
**Flexion (PI) malposition is literally just the opposite — see pg. 32 in notepacket**
What are pain patterns for Extension (AS) versus Flexion (PI) malposition?
Same for both — referred pain in buttock, posterior thigh, groin
What are knee pains in Extension (AS) malposition versus Flexion (PI) malposition?
AS — lateral knee, TFL
PI — medial knee, sartorial insertion
