hip part 2 Flashcards
what makes up the structure of the acetabulum?
fusion of the following 3 bones:
pubis 1/5
ischium 2/5
ilium 2/5
how long does it take for full ossification of the acetabulum and why is it important?
15-25 years
important bc if lateral fall in younger growing years theres a weakened acetabulum bc not fully developed
what is the structure of the acetabulum?
horseshoe shaped articular area
fibrocartilagenous labrum (thick which contributes to strength of the joint)
transverse acetabular ligament ( spans articular gap, forms roof of tunnel)
what is the spatial orientation of the acetabulum?
faces laterally, anteriorly, and inferiorly
for males and females what is the normal anterior location of the acetabular?
18.5º males
21.5º females
for males and females what is the normal inferior location of the acetabular?
22º-42º range
average 38º males
average 35º females
what makes up the center edge angle?
center point of the head of the femur
vertical (longitudinal) reference line up
final line drawn to most lateral aspect of the osseous part of the acetabulum
what happens to the center edge angle with age?
it increases with age because of wolffs law boney spurs and osseous growths increases the osseous part of the acetabulum increasing the angle
what are the 3 ways the acetabular changes with aging and the benefit or problem with each?
ossification of the articulation of the three bones of the pelvis- increased “central stability”
decreased acetabular “roundness”- reduced co-aption (lose ROM)
increased center edge angle- increased superior stability
what is the structure of the proximal femur?
more spherical than acetabulum
fovea capitis- could be torn with artery if dislocated which leads to necrosis of femoral head
what is the spatial orientation of the proximal femur?
projects medial, superior and anterior
what is important of the acetabulum and femur spatial orientation?
both the acetabulum and femur head are anterior so doesn’t line up which creates increased mobility. The other 2/3 components line up which increase stability
what is the angle of inclination?
the frontal plane angulation between the shaft and neck of femur
what does the angle of inclination contribute to?
the normal valgus position of the knee
what happens to the angle of inclination over time?
decreases with age
150º early infancy
125º in adults
120º in elderly
why does the angle of inclination decrease with time?
due to the bending moment at the femoral neck due to constant pull of gravity
what is coxa valga?
increase angle
increase leg length produces hip adduction
increase “pre-load” to hip abductors
decrease moment arm of abductors
what could coxa valga or greater leg length lead to over time?
joints above and below would have to side bend opposite direction to compensate
what is coxa vera?
decrease angle
decrease leg length
relative hip abduction
poor hip abductor length tension relationship
impingement may limit abduction ROM
stress concentration superior contact area
what could coxa vara or decreased leg length lead to over time?
force capability will be compensated so decreased torque of glute med and TFL
can lead to DJD (hip OA)
T/F: coxa vara can be congenital, developmental or traumatic
true
what are some positives of coxa vara?
increased moment arm for hip abductor force
alignment may improve joint stability