Unit 2- Hip Flashcards
What is the position of max congruence between femur and acetabulum when NWB
hip flexion, abduction, slight ER
what is the close packed position of the hip
hip extension, IR, abduction
angle of inclination
angle between the shaft and neck, normally 125
decreases during WB
acetabular dome
primary wb surface of acetabulum
center edge angle
angle formed by center of head of femur and edge of acetabulum connection with femur head
how to increase stress on the acetabulum
decrease center edge angle, acetabular anteversion
how to decrease stress on the acetabulum
increase contact area (happens during gait)
bony adaptation to weight bearing
tubecular areas
primary: medial- vertical compressive forces
lateral- oblique; response to shear/tensile forces
secondary: tensile and compressive, in shaft
zone of weakness in femur
where no compressive forces are usually found, vulnerable to dislocation
what are the roles of the hip joint ligaments
iliofemoral: limit extension, lateral rotation
pubofemoral: limit extension, lateral rotation
ischiofemoral: limit extension, adduction, medial rotation
what is the alignment of the bony landmarks of the pelvis in neutral
asis in line with psis in line with pubic symphysis
Anterior/posterior pelvic tilt
named by movement of ASIS
sagittal plane
lateral pelvic tilt
aka pelvic hike/drop
named by movement of side opposite the WB limb (muscles of stance leg control motion of far side of pelvis
frontal plane, A/P axis in middle of femoral head of stance leg
forward/backward pelvic rotation
transverse plane
named by side opposite the WB limb
lumbopelvic rhythm
describes how lumbar spine is moving relative to pelvis
ipsidirectional- maximize angular displacement of the entire trunk relative to lower extremity
contradirectional- keeps supralumbar trunk stable
pelvifemoral motion
combined motion of pelvis and femur increases the available motion
ex- touching toes, anterior pelvic tilt
hip abduction, tilt hip and side bend to increase abduction
Force couple for anterior pelvic tilt
iliopsoas (reverse motion) and erector spinae
cocontract to contribute to rotation in same direction
force couple for posterior pelvic tilt
glut max, hamstrings, rectus abdominus
function of hip adductors
aim to bring the hip to about 60 degrees flexion
more flexion–extensor
more extension–flexor
what limits hip flexion with knee flexed
posterior and inferior capsule, glut max
what limits hip flexion with knee extended
hamstrings
what limits hip extension with knee extended
iliofemoral ligament, anterior capsule, pubofemoral and ischiofemoral, iliopsoas
what limits hip extension with knee flexed
rec fem
what limits abduction
adductor muscles, pubofemoral ligament
what limits adduction
ITB abductor muscles (TFL and glut med)
what limits internal rotation
ischofemoral ligament, external rotator muscles (glut max and piriformis)
what limits external rotation
iliofemoral and pubofemoral, internal rotator muscles (TFL, glut min)
what is normal acetabular anteversion
20 degrees
coxa vara
less than 125 degrees angle of inclination
- increased moment arm for hip adductor force
- more stability
- increases bending moment are, increases bending moment, increases shear force across femoral neck
- decreased functional length of hip abductor
coxa valga
more than 125 degrees angle of inclination
- decreased bending moment arm, decreases bending moment and shear force across femoral neck
- increases function length of hip abductor muscle
- decrease moment arm for hip abductor force
- alignment may favor hip dislocation (more mobility)
