The Hip Joint

Question 1

function of hip joint

Answer 1

• support weight of HAT (head, arms, trunk)

- transmits force between pelvis & LE

Question 2

type of joint (hip) & the degrees of freedom

Answer 2

• triaxial diarthrodial
• ball & socket
• 3 deg of freedom (flex/ext, IR/ER, abduct/adduct)

Question 3

anatomy of the hip joint (what is on/around it)

Answer 3

• head & acetabulum
• loose capsule
• ligaments
• strong musculature

Question 4

Anatomy of acetabulum

Answer 4

• covered with thick articular cartilage
• horseshoe shaped: superior articulating area
• fibrocartilage labrum: wedge shaped

Question 5

trabecular lay down cells in the ________ due to ______

Answer 5

acetabulum; stress

b/c acetabulum is a weight bearing area!

Question 6

Center edge angle aka angle of Wilberg

Answer 6

• angle between vertical & antero-lateral rim
• degree of inferior tilt
• most common joint for congenital dislocations
  norm - 20-40 deg

Question 7

Smaller center edge causes ________, leading to a ________ risk of __________

Answer 7

diminished head coverage, leading to an increased risk of superior dislocation

Question 8

Center edge angle ________ with age, causing children to be ______ susceptible to dislocation

Answer 8

increases; more

Question 9

Acetabular aversion “norms”

Answer 9

19 - 40 degrees

Question 10

pathological issues of acetabular aversion causes:

Answer 10

decreased stability, ultimately causing anterior dislocation

Question 11

Acetabulum - labrum

Answer 11

deepens socket, causing an increase in concavity
- grasps the head of femur

labrum: fibrocartilage wedge shape

Question 12

Femoral head

Answer 12

• 2/3 of a sphere
• covered by articular cartilage
• fovea

Question 13

fovea

Answer 13

ligament of head of the femur (ligamentum teres)

- carries neurovascular supply to head of femur

Question 14

Femoral head - angle of inclination

Answer 14

frontal plane

congruency occurs at 125 deg in adults – decreases with age 150 –> 120 deg

Question 15

COXA VALGA

femoral head angle of inclination

Answer 15

greater than 125 degrees

valgus at hip contributes to veras at knee

Question 16

COXA VERA

Answer 16

less than 125 degrees

veras at hip contributes to valgus at knee

Question 17

femoral head- angle of torsion

Answer 17

• transverse plane
• angle between femoral neck & condyles
  averages 12-15 degrees in normal adults

Question 18

anteversion

Answer 18

TOE IN

increase in torsion angle –> internal femoral torsion

Question 19

retroversion

Answer 19

TOE OUT

decrease in torsion angle –> external femoral torsion

Question 20

Hip joint congruence

Answer 20

• very congruent but not perfect b/c we need to weight bear and we need “cushion” to do so
• acetabulum does not cover head superiorly
• only periphery of acetabulum is articular
• deep acetabular fossa important for vacuum - sucks femoral head in the fossa

Question 21

pathological angle of inclination/torsion causes:

Answer 21

less congruency, leading to instability

Question 22

Change in center edge can alter ______ causing a ______ in stability

Answer 22

congruency; decrease

Question 23

Hip joint capsule

Answer 23

• strong & dense –> important for stability
• attaches to periphery of acetabulum and blends with labrum
• covers femoral neck & attaches to base of neck

Question 24

Iliofemoral ligament

Answer 24

ANTERIOR

• Y ligament of Bigelow
• AIIS to the intertrochanteric line
• checks hip extension

(check = prevents/resists)

Question 25

Pubofemoral ligament

Answer 25

ANTERIOR - pubic ramus to intertrochanteric fossa - taut in abduction & extension

Question 26

Ischiofemoral ligament

Answer 26

POSTERIOR | - femoral neck to acetabular rim/labrum

Question 27

Ischiofemoral ligament horizontal fibers tighten during:

Answer 27

ABDUCTION

Question 28

Ischiofemoral ligament spiral fibers tighten during _____ & loosen during ________

Answer 28

extension; flexion

Question 29

Ischiofemoral ligament during close-packed position:

Answer 29

extension

Question 30

ligament of head of femur

Answer 30

- Doesn't play a major role in stability - Neurovascular conduit (especially in young since vessels can't cross cartilaginous endplates) == circumflex femoral artery

Question 31

Weight bearing structures

Answer 31

- intricate trabeculae arrangement in femur & pelvis | - increase subchondral boned density in superior acetabulum primary weight bearing surface

Question 32

Zone of weakness

Answer 32

- region of femoral neck - susceptible to bending forces - fracture 2 deg to increase forces or tissue changes (i.e. osteoporosis)

Question 33

Arthrokinematics: | Neurtal flex/extend-

Answer 33

almost a pure spin

Question 34

arthrokinematics: | outside of neutral-

Answer 34

combined spin & glide

Question 35

arthrokinematics: | IR/ER & abduct/adduct-

Answer 35

spin & glide

Question 36

arthrokinematics: | weight bearing femur fixed -

Answer 36

concave on convex (same direction)

Question 37

Osteokinematics - normal flexion (ROM)

Answer 37

120 - 135 deg

Question 38

Osteokinematics - normal extension ROM

Answer 38

10 - 30 deg

Question 39

osteokinematics - normal abduction ROM

Answer 39

30 - 50 deg

Question 40

Osteokinematics - normal adduction ROM

Answer 40

10 - 30 deg

Question 41

Osteokinematics - normal ER ROM

Answer 41

45 - 60 deg

Question 42

Osteokinematics - normal IR ROM

Answer 42

30 - 45 deg

Question 43

Functional hip ROM - flexion

Answer 43

124 deg | tying a shoe or squatting

Question 44

Functional hip ROM - extension

Answer 44

10 deg | gait

Question 45

functional hip ROM - abduction

Answer 45

28 deg | squatting

Question 46

functional hip ROM - ER

Answer 46

75 - 90 deg | foot across opposite thigh

Question 47

HAT = ____ of total Body weight

Answer 47

2/3

Question 48

each LE is _____ of total body weight

Answer 48

1/6 1/6 + 1/6 = 1/3

Question 49

compression on the hip (due to grav) during a unilateral stance can be calculated by

Answer 49

``` (HAT + LE) x BW ex- let BW = 180 lbs (2/3 + 1/6) x 180 = 5/6 x 180 = 150 lbs ```

Question 50

Maintaining static equilibrium

Answer 50

1st determine torque at hip due to gravity - Moment arm from AOR to LOG = 4 inches - Adduction torque = force x MA (perp distance) = (5/6)(BW)(MA) =150 x 4 = 600 in-lbs

Question 51

hip _____ exert an equal counter torque to maintain equilibrium/balance

Answer 51

abductors

Question 52

compensatory lean when experiencing hip pain occurs on which side???

Answer 52

towards the affected limb | - compression on hip joint remains the same due to gravity

Question 53

compensatory lean: LOG moves ___to or from?___ hip joint AOR

Answer 53

towards! - reduces the HAT moment arm - reduces the total force put on hip so it feels less painful when you do a compensatory lean

Question 54

Which hand to we put cane in

Answer 54

contralateral side | side opposite of injury

Question 55

why do we give ppl walkers/canes

Answer 55

compensatory lean causes wear & tear

Question 56

why do we put the cane on the opposite side of injury

Answer 56

so they gluteus minims & medius don't have to do work.... cane pushes you back upright (w/ lat dorsi & arm) - -- muscles will have to generate less force to work - - promotes upright posture

Question 57

what happens when you put the cane on the ipsilateral side????

Answer 57

muscles will need to work just as hard with the cane as without the cane