Biomechanics Quiz 5 Flashcards
What kind of joint is the hip complex? form?
- synovial joint
- - ball and socket
How many angular rotations (degrees of freedom) in hip?
3 DOF
How many translations in hip?
3 DOF
What does the hip complex support?
support for: 1. head 2. arm 3. trunk (HAT)
hip complex joint arrangement (2 joints)
- pelvis joint: superior
2. femur joint: inferior
(osteology) shape of proximal femur – 3 influencing factors:
- force of muscle activation
- weight bearing
- circulation
what bone is the longest and strongest in the human body?
femur
(femur) angle of inclination = “angulation of femur in proximal plane”
what are the 3 angles?
- normal (angled up 125*) BEST
- coxa vara (angled up less 105*)
- coxa valga (angled up way too high 140*+
coxa vara 105* – 3 possible issues
- shortening of limb
- femoral neck fraction
- capital epiphyseal slipping (adolescence)
coxa valga 140* – 3 issues
- angle at birth 140-150* degrees and weight bearing changes forces.
- lengthening of limb
- hip dislocation
femoral torsion – 3 types and their angle *degrees
- normal anteversion = 15*
- excessive anteversion = 35*
- retroversion = 5*
excessive anteversion increases likelihood of:
a. hip dislocation
b. articular incongruence
c. increased joint contact force
d. increased wear on articular cartilage
excessive anteversion in children causes and how to fix:
- in-toeing
- - fix: strengthen external rotators
femoral head is made of 2 things:
- hyaline cartilage - C shape
2. ligamentum trees connects to fibia capitus and protects blood vessel
what does acetabulum contact area do for body?
provides stability at hip joint.
(Arthology) 3 capsule ligaments of the hip
- iliofemoral
- ischiofemoral
- pubofemoral
resists tension the most (STRONGEST)
iliofemoral
at midstance, the lunate surface is being …
… fully loaded
why glenoid labrum isn’t super important in hip.
it’s really shallow, which is why we lift our arms up over our head. But at hip, we don’t need a lot of extra stability because osteology / bony shape gives it a ton of stability.
Arthology: Iliofemoral is also called the …
“Y-ligament”
which of the 3 capsule ligaments of the hip resist hip extension?
trick question … ALL 3!
center of mass for iliofemoral
behind rotation
when taut, the iliofemoral is used for:
a. hip extension
b. hip ER
iliofemoral on crutches …
passive tension with standing
when taut, pubofemoral is used for:
a. hip abduction
b. extension
when taut, ischiofemoral is used for:
a. hip extension
b. hip IR
(femoral-on-pelvic hip rotation) for sagittal plane, flexion is what degrees? extension is?
flexion: 120*
extension: 20*
(femoral-on-pelvic hip rotation) for frontal plane, abduction is what degrees? adduction is?
abduction: 40*
adduction: 20*
(femoral-on-pelvic hip rotation) for horizontal plane, internal rotation is what degrees? external rotation is?
internal: 40*
external: 40*
(osteology: femur) which has the greater articular surface? medial or lateral?
medial
regarding the curvature of femoral condyles in sagittal plane, which is greater joint congruency and stability? extension or flexion?
extension
what kind of bone is patella?
sesamoid bone
what type of cartilage is the patella made of?
hyaline
(osteology: tibia) which articular surfaces are smaller? the tibia or femur?
tibia
which plateau bears more load during weight bearing? medial or lateral?
medial tibia – it allows for greater stress distribution
tibofemoral (TF) alignment: normal TF alignment
170-175* external angle
tibofemoral (TF) alignment: abnormal TF alignment – genu valgum and verum
genu valgum = <165* (knocked knees)
gene verum = >180* (bow legs)
Know how to draw the knee alignment!
tibofemoral (TF) alignment: gene valgum is abduction or adduction?
abduction
tibofemoral (TF) alignment: gene verum is abduction or adduction?
adduction
