Hip Flashcards
T/F: The hip joint can move in all 3 planes.
true: horizontal, frontal, sagittal
What structure in the hip joint increases congruency and surface area?
labrum
T/F: The shape of the hip joint is well suited for stability.
true
What is the angle of inclination? What’s a normal value for this angle?
- angle of inclination = how angled up the head of the femur is
- measured via line through shaft of femur and line through neck of femur
- normal = 125 deg
If the angle of inclination is less than 125 degrees, what is the term for this? What can this cause at the knee?
coxa vara, can cause genu valgus at the knee
What are the benefits and disadvantages from having an angle of inclination less than 125 degrees?
advantage -
1) increased moment arm for abductors, improving force
2) alignment may improve joint stability
disadvantage-
1) increased bending moment arm, which increases sheer force at femoral neck
2) shortens the fibers for glut med, completely negating the better moment arm
At what age is the angle of inclination permanent?
5 yo
What does the angle of inclination impact?
fiber arrangement/length, moment arm, joint alignment and stability
With coxa valga, what is the angle of inclination?
greater than 125, more like 150
T/F: We start out with coxa valga at birth.
true, start at 150 deg and then it gets to 125
What are the negatives about having a coxa valga?
1) decreased moment arm for hip abductors
2) poor alignment favors dislocation
Increased sheer force on the femur neck occurs with what angle of inclination deformity?
coxa vara
Increased fiber length of abductors is a pro for what, coxa vara or coxa valga?
coxa valga
Decreased moment arm is a disadvantage for coxa vara or coxa valga?
coxa valga
In which deformity, coxa valga or vara, is the femur more likely to dislocate?
coxa valga, >125
What are the positives and negatives for coxa valga?
- positives = decreased sheer forces on neck, increased abductor fiber length
- negatives = easy dislocation, decreased moment arm for force of abductors
What are the positives and negatives for coxa vara?
- positives = increased stability, increased moment arm for abductor force
- negatives = shortened fiber length of abductors, more sheer force on neck
What is femoral torsion? How do you assess this, what position must the patient be in?
- how the femoral head and neck align with the condyles below
- patient must be prone
How is torsion measured? What’s a normal torsion angle?
- Line through condyles and line through neck of femur
- normal torsion angle = 15 degrees anteversion (head twisted forward)
What is the normal angle of torsion for a baby? When does it resume the normal angle value?
~35 degrees, weight bearing decreases this angle till it’s normal around 17/18 yo
What classifies a femur as retroverted?
What can excessive anteversion do to the adult? (3)
1) decrease abductor moment arm
2) destabilize joint
3) articular incongruence
How do we compensate for coxa vara/valga?
by going into genu valgus/varus at the knee, respectively
How do we compensate for retroversion? Anteversion?
retroversion = toe out to compensate anteversion = toe in to compensate
What can accompany coxa vara?
coxa vara = genu valgus = anteversion = toeing in
Why is toeing in and out a bad compensation?
it may lead to more joint stability, but toeing out shortens the external rotators
- pt may complain of butt pain and present with limited internal rotation ROM
T/F: Excessive torsion can cause femoral anteversion.
true
What does the acetabular anteversion angle tell you? What’s normal?
tells you how well the anterior acetabulum covers the anterior head of the femur; normal is 20 degrees
In what plane do you assess the acetabular anteversion angle?
in the horizontal plane
T/F: The closed pack position for the hip is the same as the most congruent position for the hip.
false!! this is the only joint where it’s not like that
What are open and closed pack positions for the hip?
- open = 30 degrees flexion, 30 deg abduction, slight ER
- closed = full extension with slight IR and abduction
What is the position of maximal congruency for the hip?
90 deg flexion, moderate ER and abduction
- capsule and ligaments on slack here tho, not much passive tension on joint here
T/F: Too little of an acetabular anteversion angle can cause osteoarthritis.
true, as well as dislocation
What ligament is most important in preventing hip extension?
iliofemoral (y-ligament)
What hip ligament is the only ligament resisting IR?
ischiofemoral ligament
What is the position of comfort for the hip?
30 deg flexion
30 deg abduction
slight ER
When is the iliofemoral ligament taut?
in extension and ER
The superior fibers of what ligament become taut in full adduction?
ischiofemoral
What ligament is taut in abduction, extension, and ER?
pubofemoral
What ligament assists in walking with forward hand-held crutches? How does it do this?
y-ligament
- the line of gravity (and body weight) is now way posterior to the hip, and the y-ligament becomes especially taut to resist that extension moment
What limits hip flexion when the knee is bent?
gluteus maximus and posterior capsule
What limits hip flexion when the knee is straight?
hamstrings and posterior capsule
What’s the difference in PROM for hip flexion when knee is flexed and knee is straight?
knee flexed = 120 deg
knee straight = 70-80 deg
Can you get more hip extension when the knee is flexed or when the knee is straight?
more with knee extended = 0-20 deg (hip ligaments and iliopsoas resist)
- only like 5 deg with knee bent due to stretching of rectus femoris
How much abduction ROM do we get, and what limits it?
- abduction = 40 deg
- limited by pubofemoral
How much adduction ROM do we get, and what limits it?
- adduction = 25 deg
- limited by ischiofemoral superior fibers, contralateral limb, and tight abductors
Do we get more internal or external rotation?
more external (45) vs internal (35)
What limits internal rotation?
ischiofemoral superficial fibers and external rotators
What limits external rotation?
iliofemoral, pubofemoral, internal rotators
What is the lumbopelvic rhythm? When is it ipsidirectional and when is it contradirectional?
lumbopelvic rhythm = when pelvis and lumbar spine rotate together
1) ipsidirectional = during far reach we want both lumbar spine and pelvis to rotate forward
2) contradirectional = during gait, pelvis rotates forward and L-spine rotates back to keep eye gaze up
What offsets the tenency of supralumbar trunk to follow anterior pelvic rotation?
lumbar lordosis limits anterior pelvic tilt
Do we get more anterior tilt when sitting or standing? Why?
more in sitting (30 deg) than standing (20 deg) because the tissues are relaxed in sitting
When weight-bearing limb goes into IR, what happens at the contralateral pelvis?
IR = contralateral pelvis moves forward (ER = pelvis moves backward
When a weight-bearing limb adducts, what happens at the contralateral pelvis?
hip lowers on contralateral side (vs hip hike when opposite limb abducts)
T/F: Full potential of pelvis-on-femur rotation requires lumbar spine and trunk to follow pelvis.
true
T/F: Spine side-bends toward abducted limb during pelvis-on-femur abduction.
false, side bends away from abducted limb, side bends toward adducted limb
Is the spine convex or concave on the abducted limb side?
convex on abducted limb
concave on adducted limb
When NWB limb swings forward during gait, what does the opposite stance limb do?
internally rotate
What arthrokinematics occur at the hip for femur-on-pelvis IR?
IR = anteriomedial roll, posteriolateral slide of femur head on acetabulum
What arthrokinematics occur during hip abduction?
ab = rolls superiolaterally, slides inferiomedially
What arthrokinematics occur during hip extension?
ext = roll posterior and inferior, slide anterior and superior
How much ROM for hip flexion do we get?
knee bent = 120
knee straight = 70-80
How much ROM for hip extension do we get?
knee bent = 5
knee straight = 20
How much ROM for hip IR/ER do we get?
IR = 35 deg ER = 45 deg
Besides hip flexion, can iliopsoas do any other movements?
- some adduction when leg is abducted
- some ER when limb is abducted
What does sartorius do?
hip flexion, abduction, external rotation
What does TFL do?
abduction, hip flexion, IR, stabilizes knee
What muscle is both a hip flexor and knee extender?
rectus femoris
Why is a lumbar lordosis sometimes painful?
There’s a lot of sheer forces at L5-S1 with excessive lordosis, as well as facet compression
What helps offset the anterior tilt of the pelvis during swing phase of gait? (when femur flexes)
abdominals
Which hip adductor is a powerful hip extensor?
adductor magnus
In what position do the adductors generate flexion torque?
when hip is at 0-40 degrees flexion
When can the adductor magnus kick in for hip extension?
when hip is at 40-70 degrees of hip flexion
When can the other adductors take over some hip extension?
greater than 100 degrees of hip flexion
What’s a better hip flexor, adductor magnus or longus?
longus is a better hip flexor, magnus is a great extensor
Are the adductors internal or external rotators also?
INTERNAL
- they insert on the back of the femur, but the bowing causes the line of pull to be in line with IR
There are no muscles that do solely, purely this motion.
IR, since no muscle’s line of force lies purely in horizontal plane
When do the ERs (like piriformis, superior glut max, and posterior glut min) become IRs?
at 90 degrees of hip flexion
What muscles are secondary IRs?
pectineus
adductor longus/brevis
TFL
glut med and min, anterior fibers
What does a scissoring gait look like?
both femurs internally rotated, flexed, and adducted
Why do people with a scissoring gait have increased IR potential?
due to the poor activation of hip extensors, and the likely flexion contracture, this causes the ERs to be put in a better position to do IR, so more IR torque will be produced :(
How do we decrease a scissoring gait with therapy?
focus on activation of the gluteus max
What ERs are responsible for more IR when hip is flexed?
gluteus max, superior fibers
piriformis
gluteus min, posterior fibers
Which fibers of gluteus maximus are` external rotators?
superior fibers
What are your primary hip extensors?
gluteus max, all fibers
hamstrings (biceps femoris LH, ST, SM)
adductor magnus, posterior head
What are your secondary hip extensors?
glut med, posterior fibers
adductor magnus, anterior fibers
rest of adductors @ >70 degrees flexion
In a slight forward lean, what muscle is activating the most to keep us from bending too forward?
glut max
- in a more forward lean, the hamstrings really increase activity
What does glut min do?
- considered a primary abductor, but really more of a stabilizer
- posterior fibers of glut min do ER
T/F: All abductors are capable of producing a IR or ER torque
true
How can a muscle become a PURE abductor?
if you neutralize rotation
A person with Trendelenburg gait will compensate by side bending which way, towards the impaired glut med or away from impaired glut med?
towards impaired glut med
For every lb you weigh, how much does it take for gluteus medius to stabilize your hip joint?
it takes twice that what you weight for glut med to stabilize your hip joint
- JRF is three times that weight
For each 1 lb. reduction in body weight, how much “weight” does that unload on the hip?
3 lbs
When is abductor torque maximized?
when limb is at neutral or even slightly adducted (the muscle length is at its longest here)
What are the primary ERs of the hip?
gluteus max and the short ERs (piriformis, gemellae, obturator internus, and quadratus femoris)
What muscle is strained in a groin pull?
adductor longus, by trying to decelerate ER
What arthrokinematics occur with hip flexion? What’s the direction of the spin?
rolls anterior and superior, slides posterior and inferior (femur spins posterior)
“Femur spinning anterior” describes what motion?
hip extension
What can the superior fibers of glut max do?
hip ER
What fibers of glut med are secondary hip extensors?
posterior fibers do hip extension
What do the posterior fibers of glut min do? What do the posterior fibers of glut med do?
posterior glut med = hip extension
posterior glut min = hip ER
What are your primary and secondary abductors of the hip?
primary = GLUT MED, glut min, TFL secondary = piriformis, sartorious
