Biomechanics of Hip and Pelvis Flashcards Preview

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Flashcards in Biomechanics of Hip and Pelvis Deck (35)
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1
Q

Describe the sagittal plane of motion for the hip.

A

anterior/posterior tilt

2
Q

describe the frontal plane of motion for the hip.

A

left lateral pelvic tilt (left side moves upward)

right lateral pelvic tilt (right side moves upward)

3
Q

describe the transverse plane of motion for the hip.

A

left transverse pelvic tilt (left side moves posterior)

right transverse pelvic tilt (right side moves posterior)

4
Q

what is the angle of inclination formed by?

A

angle in teh FRONTAL plane formed by the axis of the head and neck of the femur and shaft of the femur

5
Q

what is the angle of inclination in infants?adults?

A

infants- 150 degree
adults- 125 degrees
(the angle of inclination decreases by 25 degrees from infancy to adulthood)

6
Q

what is a decrease in the angle of inclination called?

A

coxa vara (genu valgum)- distal femur is directed towards the midline and the knees are closer together

7
Q

what is an increase in teh angle of inclination called?

A

coxa valga (genu varum) - distal femur is directed away from the midline and the knees are farther apart

8
Q

what is the purpose of normal inclination angle?

A

allows abductors to function with a mechanical advantage as they counterbalance body weight in one-legged stance

9
Q

where should hip abductors be to achieve muscle stability which is maximum when the child begins to stand? (one-legged)

A

hip abductors should be as far laterally from the hip (fulcrum) to increase the lever arm

10
Q

what is alsberg’s angle?

A

(similar to angle of inclination) - angle formed by the line thru the epiphyseal plate of the neck of the femur and the long axis of the femur

11
Q

what is normal alsberg’s angle?

A

41 degrees

12
Q

an increase in alsberg’s angle would be called what? a decrease?

A

increase- coxa valga (genu varum)

decrease- coxa vara (genu valgum)

13
Q

what is the angle of declination?

A

angle in the TRANSVERSE plane formed by the axis of the neck of the femur and the transcondylar axis of the knee with the apex of teh angle lateral

14
Q

what is the angle of declination in infants? adults?

A

infant: 30-60 degrees of internal rotation
adults: 8-12 degrees of internal rotation

15
Q

what is femoral anteversion?

A

normal internal femoral shaft rotation for angle of declination

16
Q

Name the hip external rotators.

A
*mnemonic- go out and get some quality players
gluteus maximus
obturators
adductors
gemelli
sartorius
quadratus femoris
piriformis
17
Q

Name the internal hip rotators.

A

gluteus medius and minimus

18
Q

what is the normal fetal position?

A

(like buddha)
hips and knees flexed
hips externally rotated
legs and feet internally rotated

19
Q

what allows maximal rotation of hip in flexed position?

A

femoral anteversion

20
Q

what is teh angle of inclination?

A

angle created from the adducted position of the femur

21
Q

how do you calculate neutral femoral position (NFP)?

A

NFP = max. external rotation - (external rot+ internal rot/2)

22
Q

what does a negative value for NFP indicate?

A

there is more internal rotation than external rotation

23
Q

if NFP is the same with the hip flexed and extended, what does this indicate?

A

rotation is due to bony changes (in femur)

24
Q

if NFP is different btwn hip flexed and extended, what does this indicate?

A

rotatio is due to a soft tissue contracture

25
Q

what is the NFP for infants?

A

(3:1 ratio)
external- 60- 90 degrees
internal- 0-30 degrees

26
Q

what is the NFP for up to 1 y/o?

A

(2:1 ratio)
external- 50-60 degrees
internal- 30 degrees

27
Q

what is the NFP for up to 4y/o?

A

(1:1 ratio)
external- 45 degrees
internal- 45 degrees

28
Q

which ligament is tightened with the hip flexed?

A

ischiofemoral ligament

29
Q

what could be a cause of decreased internal hip ROM (same as increased external hip ROM)?

A

shortened or taut ischiofemoral ligament

30
Q

which ligament is tightened with hip extended?

A

iliofemoral, puboscapular, ligamentum teres

31
Q

what could be the cause of decreased external hip ROM (same as increased internal hip ROM)?

A

shortened or taut iliofemoral, puboscapular, ligamentum teres

32
Q

what is the needed amt of hip flexion/extension?

A

flexion- at least 120-130

extension- 0-20

33
Q

what is the needed amt of hip abduction/adduction?

A

hip abudction- 40-45

hip adduction- 20-25

34
Q

what are you testing when you have patient supine, flex the hip and knee to 90 and slowly rotate the leg outwards (externally) as you gradually extend the knee?

A

testing medial hamstring tightness

-examiner will be unable to achieve 160 degrees of knee extension

35
Q

what are you testing when you have patient supine, flexed hip and knee, and slowly rotate the knee internally as you gradually extend the knee?

A

testing lateral hamstring tightness