Biomechanics Quiz 5

Question 1

What kind of joint is the hip complex? form?

Answer 1

• • synovial joint

- - ball and socket

Question 2

How many angular rotations (degrees of freedom) in hip?

Answer 2

3 DOF

Question 3

How many translations in hip?

Answer 3

3 DOF

Question 4

What does the hip complex support?

Answer 4

support for: 
1. head
2. arm
3. trunk 
(HAT)

Question 5

hip complex joint arrangement (2 joints)

Answer 5

1. pelvis joint: superior

2. femur joint: inferior

Question 6

(osteology) shape of proximal femur – 3 influencing factors:

Answer 6

1. force of muscle activation
2. weight bearing
3. circulation

Question 7

what bone is the longest and strongest in the human body?

Answer 7

femur

Question 8

(femur) angle of inclination = “angulation of femur in proximal plane”

what are the 3 angles?

Answer 8

1. normal (angled up 125*) BEST
2. coxa vara (angled up less 105*)
3. coxa valga (angled up way too high 140*+

Question 9

coxa vara 105* – 3 possible issues

Answer 9

1. shortening of limb
2. femoral neck fraction
3. capital epiphyseal slipping (adolescence)

Question 10

coxa valga 140* – 3 issues

Answer 10

1. angle at birth 140-150* degrees and weight bearing changes forces.
2. lengthening of limb
3. hip dislocation

Question 11

femoral torsion – 3 types and their angle *degrees

Answer 11

1. normal anteversion = 15*
2. excessive anteversion = 35*
3. retroversion = 5*

Question 12

excessive anteversion increases likelihood of:

Answer 12

a. hip dislocation
b. articular incongruence
c. increased joint contact force
d. increased wear on articular cartilage

Question 13

excessive anteversion in children causes and how to fix:

Answer 13

• • in-toeing

- - fix: strengthen external rotators

Question 14

femoral head is made of 2 things:

Answer 14

1. hyaline cartilage - C shape

2. ligamentum trees connects to fibia capitus and protects blood vessel

Question 15

what does acetabulum contact area do for body?

Answer 15

provides stability at hip joint.

Question 16

(Arthology) 3 capsule ligaments of the hip

Answer 16

1. iliofemoral
2. ischiofemoral
3. pubofemoral

Question 17

resists tension the most (STRONGEST)

Answer 17

iliofemoral

Question 18

at midstance, the lunate surface is being …

Answer 18

… fully loaded

Question 19

why glenoid labrum isn’t super important in hip.

Answer 19

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.

Question 20

Arthology: Iliofemoral is also called the …

Answer 20

“Y-ligament”

Question 21

which of the 3 capsule ligaments of the hip resist hip extension?

Answer 21

trick question … ALL 3!

Question 22

center of mass for iliofemoral

Answer 22

behind rotation

Question 23

when taut, the iliofemoral is used for:

Answer 23

a. hip extension

b. hip ER

Question 24

iliofemoral on crutches …

Answer 24

passive tension with standing

Question 25

when taut, pubofemoral is used for:

Answer 25

a. hip abduction | b. extension

Question 26

when taut, ischiofemoral is used for:

Answer 26

a. hip extension | b. hip IR

Question 27

(femoral-on-pelvic hip rotation) for sagittal plane, flexion is what degrees? extension is?

Answer 27

flexion: 120* extension: 20*

Question 28

(femoral-on-pelvic hip rotation) for frontal plane, abduction is what degrees? adduction is?

Answer 28

abduction: 40* adduction: 20*

Question 29

(femoral-on-pelvic hip rotation) for horizontal plane, internal rotation is what degrees? external rotation is?

Answer 29

internal: 40* external: 40*

Question 30

(osteology: femur) which has the greater articular surface? medial or lateral?

Answer 30

medial

Question 31

regarding the curvature of femoral condyles in sagittal plane, which is greater joint congruency and stability? extension or flexion?

Answer 31

extension

Question 32

what kind of bone is patella?

Answer 32

sesamoid bone

Question 33

what type of cartilage is the patella made of?

Answer 33

hyaline

Question 34

(osteology: tibia) which articular surfaces are smaller? the tibia or femur?

Answer 34

tibia

Question 35

which plateau bears more load during weight bearing? medial or lateral?

Answer 35

medial tibia -- it allows for greater stress distribution

Question 36

tibofemoral (TF) alignment: normal TF alignment

Answer 36

170-175* external angle

Question 37

tibofemoral (TF) alignment: abnormal TF alignment -- genu valgum and verum

Answer 37

genu valgum = <165* (knocked knees) gene verum = >180* (bow legs) Know how to draw the knee alignment!

Question 38

tibofemoral (TF) alignment: gene valgum is abduction or adduction?

Answer 38

abduction

Question 39

tibofemoral (TF) alignment: gene verum is abduction or adduction?

Answer 39

adduction